Re-apply formatting to SUMMARY.md

With the latest version of mdbook-i18n-helpers, we now have support
for formatting in the `SUMMARY.md` file. This allows us to revert the
changes made in #130 when we first introduced the translation support.

This also aligns a few headings to match the heading in the outline.
While this isn’t strictly necessary, it removes a bit of work for the
translators.

src/SUMMARY.md

@@ -31,37 +31,37 @@
   - [References](basic-syntax/references.md)
     - [Dangling References](basic-syntax/references-dangling.md)
   - [Slices](basic-syntax/slices.md)
-    - [String vs str](basic-syntax/string-slices.md)
+    - [`String` vs `str`](basic-syntax/string-slices.md)
   - [Functions](basic-syntax/functions.md)
     - [Rustdoc](basic-syntax/rustdoc.md)
     - [Methods](basic-syntax/methods.md)
     - [Overloading](basic-syntax/functions-interlude.md)
 - [Exercises](exercises/day-1/morning.md)
   - [Implicit Conversions](exercises/day-1/implicit-conversions.md)
-  - [Arrays and for Loops](exercises/day-1/for-loops.md)
+  - [Arrays and `for` Loops](exercises/day-1/for-loops.md)
 
 # Day 1: Afternoon
 
 - [Control Flow](control-flow.md)
   - [Blocks](control-flow/blocks.md)
-  - [if expressions](control-flow/if-expressions.md)
-  - [for expressions](control-flow/for-expressions.md)
-  - [while expressions](control-flow/while-expressions.md)
-  - [break & continue](control-flow/break-continue.md)
-  - [loop expressions](control-flow/loop-expressions.md)
+  - [`if` expressions](control-flow/if-expressions.md)
+  - [`for` expressions](control-flow/for-expressions.md)
+  - [`while` expressions](control-flow/while-expressions.md)
+  - [`break` & `continue`](control-flow/break-continue.md)
+  - [`loop` expressions](control-flow/loop-expressions.md)
 
 - [Variables](basic-syntax/variables.md)
   - [Type Inference](basic-syntax/type-inference.md)
-  - [static & const](basic-syntax/static-and-const.md)
+  - [`static` & `const`](basic-syntax/static-and-const.md)
   - [Scopes and Shadowing](basic-syntax/scopes-shadowing.md)
 - [Enums](enums.md)
   - [Variant Payloads](enums/variant-payloads.md)
   - [Enum Sizes](enums/sizes.md)
 
 - [Novel Control Flow](control-flow/novel.md)
-  - [if let expressions](control-flow/if-let-expressions.md)
-  - [while let expressions](control-flow/while-let-expressions.md)
-  - [match expressions](control-flow/match-expressions.md)
+  - [`if let` expressions](control-flow/if-let-expressions.md)
+  - [`while let` expressions](control-flow/while-let-expressions.md)
+  - [`match` expressions](control-flow/match-expressions.md)
 
 - [Pattern Matching](pattern-matching.md)
   - [Destructuring Enums](pattern-matching/destructuring-enums.md)
@@ -110,15 +110,15 @@
 # Day 2: Afternoon
 
 - [Standard Library](std.md)
-  - [Option and Result](std/option-result.md)
-  - [String](std/string.md)
-  - [Vec](std/vec.md)
-  - [HashMap](std/hashmap.md)
-  - [Box](std/box.md)
+  - [`Option` and `Result`](std/option-result.md)
+  - [`String`](std/string.md)
+  - [`Vec`](std/vec.md)
+  - [`HashMap`](std/hashmap.md)
+  - [`Box`](std/box.md)
     - [Recursive Data Types](std/box-recursive.md)
     - [Niche Optimization](std/box-niche.md)
-  - [Rc](std/rc.md)
-  - [Cell/RefCell](std/cell.md)
+  - [`Rc`](std/rc.md)
+  - [`Cell` & `RefCell`](std/cell.md)
 - [Modules](modules.md)
   - [Visibility](modules/visibility.md)
   - [Paths](modules/paths.md)
@@ -142,16 +142,16 @@
   - [Deriving Traits](traits/deriving-traits.md)
   - [Default Methods](traits/default-methods.md)
   - [Trait Bounds](traits/trait-bounds.md)
-  - [impl Trait](traits/impl-trait.md)
+  - [`impl Trait`](traits/impl-trait.md)
 - [Important Traits](traits/important-traits.md)
-  - [Iterator](traits/iterator.md)
-  - [FromIterator](traits/from-iterator.md)
-  - [From and Into](traits/from-into.md)
-  - [Read and Write](traits/read-write.md)
-  - [Drop](traits/drop.md)
-  - [Default](traits/default.md)
-  - [Operators: Add, Mul, ...](traits/operators.md)
-  - [Closures: Fn, FnMut, FnOnce](traits/closures.md)
+  - [`Iterator`](traits/iterator.md)
+  - [`FromIterator`](traits/from-iterator.md)
+  - [`From` & `Into`](traits/from-into.md)
+  - [`Read` & `Write`](traits/read-write.md)
+  - [`Drop`](traits/drop.md)
+  - [`Default`](traits/default.md)
+  - [Operators: `Add`, `Mul`, ...](traits/operators.md)
+  - [Closures: `Fn`, `FnMut`, `FnOnce`](traits/closures.md)
 - [Exercises](exercises/day-3/morning.md)
   - [A Simple GUI Library](exercises/day-3/simple-gui.md)
   - [Points and Polygons](exercises/day-3/points-polygons.md)
@@ -162,7 +162,7 @@
   - [Panics](error-handling/panics.md)
     - [Catching Stack Unwinding](error-handling/panic-unwind.md)
   - [Structured Error Handling](error-handling/result.md)
-  - [Propagating Errors with ?](error-handling/try-operator.md)
+  - [Propagating Errors with `?`](error-handling/try-operator.md)
     - [Converting Error Types](error-handling/converting-error-types.md)
       - [Example](error-handling/converting-error-types-example.md)
     - [Deriving Error Enums](error-handling/deriving-error-enums.md)
@@ -251,13 +251,13 @@
   - [Exceptions](bare-metal/aps/exceptions.md)
   - [Other Projects](bare-metal/aps/other-projects.md)
 - [Useful Crates](bare-metal/useful-crates.md)
-  - [zerocopy](bare-metal/useful-crates/zerocopy.md)
-  - [aarch64-paging](bare-metal/useful-crates/aarch64-paging.md)
-  - [buddy_system_allocator](bare-metal/useful-crates/buddy_system_allocator.md)
-  - [tinyvec](bare-metal/useful-crates/tinyvec.md)
-  - [spin](bare-metal/useful-crates/spin.md)
+  - [`zerocopy`](bare-metal/useful-crates/zerocopy.md)
+  - [`aarch64-paging`](bare-metal/useful-crates/aarch64-paging.md)
+  - [`buddy_system_allocator`](bare-metal/useful-crates/buddy_system_allocator.md)
+  - [`tinyvec`](bare-metal/useful-crates/tinyvec.md)
+  - [`spin`](bare-metal/useful-crates/spin.md)
 - [Android](bare-metal/android.md)
-  - [vmbase](bare-metal/android/vmbase.md)
+  - [`vmbase`](bare-metal/android/vmbase.md)
 - [Exercises](exercises/bare-metal/afternoon.md)
   - [RTC Driver](exercises/bare-metal/rtc.md)
 
@@ -272,13 +272,13 @@
 - [Channels](concurrency/channels.md)
   - [Unbounded Channels](concurrency/channels/unbounded.md)
   - [Bounded Channels](concurrency/channels/bounded.md)
-- [Send and Sync](concurrency/send-sync.md)
-  - [Send](concurrency/send-sync/send.md)
-  - [Sync](concurrency/send-sync/sync.md)
+- [`Send` and `Sync`](concurrency/send-sync.md)
+  - [`Send`](concurrency/send-sync/send.md)
+  - [`Sync`](concurrency/send-sync/sync.md)
   - [Examples](concurrency/send-sync/examples.md)
 - [Shared State](concurrency/shared_state.md)
-  - [Arc](concurrency/shared_state/arc.md)
-  - [Mutex](concurrency/shared_state/mutex.md)
+  - [`Arc`](concurrency/shared_state/arc.md)
+  - [`Mutex`](concurrency/shared_state/mutex.md)
   - [Example](concurrency/shared_state/example.md)
 - [Exercises](exercises/concurrency/morning.md)
   - [Dining Philosophers](exercises/concurrency/dining-philosophers.md)
@@ -287,7 +287,7 @@
 # Concurrency: Afternoon
 
 - [Async Basics](async.md)
-  - [async/await](async/async-await.md)
+  - [`async`/`await`](async/async-await.md)
   - [Futures](async/futures.md)
   - [Runtimes](async/runtimes.md)
     - [Tokio](async/runtimes/tokio.md)
@@ -298,7 +298,7 @@
   - [Select](async/control-flow/select.md)
 - [Pitfalls](async/pitfalls.md)
   - [Blocking the Executor](async/pitfalls/blocking-executor.md)
-  - [Pin](async/pitfalls/pin.md)
+  - [`Pin`](async/pitfalls/pin.md)
   - [Async Traits](async/pitfalls/async-traits.md)
   - [Cancellation](async/pitfalls/cancellation.md)
 - [Exercises](exercises/concurrency/afternoon.md)

src/async/pitfalls/pin.md

@@ -1,12 +1,12 @@
-# Pin
+# `Pin`
 
 When you await a future, all local variables (that would ordinarily be stored on
 a stack frame) are instead stored in the Future for the current async block. If your
 future has pointers to data on the stack, those pointers might get invalidated.
 This is unsafe.
 
 Therefore, you must guarantee that the addresses your future points to don't
-change. That is why we need to `pin` futures. Using the same future repeatedly
+change. That is why we need to "pin" futures. Using the same future repeatedly
 in a `select!` often leads to issues with pinned values.
 
 ```rust,editable,compile_fail

src/control-flow/break-continue.md

@@ -1,4 +1,4 @@
-# `break` and `continue`
+# `break` & `continue`
 
 - If you want to exit a loop early, use [`break`](https://doc.rust-lang.org/reference/expressions/loop-expr.html#break-expressions),
 - If you want to immediately start