Merge the pdg construction from flowistry into this repo (#140)

## What Changed?

Merges the flowistry PDG into this repo. Contains updates to the
handling of async closures to have better field sensitivity.

Caveats: This merges an alias analysis bug #144. But I need main to
catch up and this bug does not appear to influence any use cases so I am
going ahead with this merge.

## Why Does It Need To?

This allows us to iterate faster on the actual construction algorithm.

## Checklist

- [x] Above description has been filled out so that upon quash merge we
have a
  good record of what changed.
- [x] New functions, methods, types are documented. Old documentation is
updated
  if necessary
- [ ] Documentation in Notion has been updated
- [ ] Tests for new behaviors are provided
  - [ ] New test suites (if any) ave been added to the CI tests (in
`.github/workflows/rust.yml`) either as compiler test or integration
test.
*Or* justification for their omission from CI has been provided in this
PR
    description.

.github/workflows/docs.yml

@@ -22,7 +22,7 @@ jobs:
         git config --local user.email "docmaster+github-actions[bot]@users.noreply.github.com"
         git config --local user.name "github-actions[bot]"
     - name: Install cargo-make
-      run: cargo install --force --debug cargo-make
+      run: rustup run stable cargo install --force --debug cargo-make
     - name: Prepare
       run: |
         cargo doc --document-private-items

.github/workflows/rust.yml

@@ -35,7 +35,7 @@ jobs:
           target/
         key: ${{ runner.os }}-rust-deps-${{ hashFiles('Cargo.lock', 'rust-toolchain.toml') }}
     - name: Install cargo-make
-      run: cargo install --force --debug cargo-make
+      run: rustup run stable cargo install --force --debug cargo-make
     - name: Build
       run: cargo make install
     - name: Run tests
@@ -54,7 +54,7 @@ jobs:
         path: ~/.rustup
         key: ${{ runner.os }}-rust-toolchain-${{ hashFiles('rust-toolchain.toml') }}
     - name: Install cargo-make
-      run: cargo install --force --debug cargo-make
+      run: rustup run stable cargo install --force --debug cargo-make
     - name: Run checks
       run: cargo make format-check-all
 
@@ -79,7 +79,7 @@ jobs:
           target/
         key: ${{ runner.os }}-rust-deps-${{ hashFiles('Cargo.lock', 'rust-toolchain.toml') }}
     - name: Install cargo-make
-      run: cargo install --force --debug cargo-make
+      run: rustup run stable cargo install --force --debug cargo-make
     - name: Here come the complaints
       run: cargo make clippy-check-all
 
@@ -104,6 +104,6 @@ jobs:
           target/
         key: ${{ runner.os }}-rust-deps-${{ hashFiles('Cargo.lock', 'rust-toolchain.toml') }}
     - name: Install cargo-make
-      run: cargo install --force --debug cargo-make
+      run: rustup run stable cargo install --force --debug cargo-make
     - name: Here come the complaints
       run: cargo make doc-check