Add examples to LazyString docstrings (#44514)

base/strings/lazy.jl

@@ -9,6 +9,15 @@ of functions).
 This type is designed to be cheap to construct at runtime, trying to offload
 as much work as possible to either the macro or later printing operations.
 
+# Examples
+
+```jldoctest
+julia> n = 5; str = LazyString("n is ", n)
+"n is 5"
+```
+
+See also [`lazy"str"`](@ref).
+
 !!! compat "Julia 1.8"
     `LazyString` requires Julia 1.8 or later.
 """
@@ -26,6 +35,16 @@ Create a [`LazyString`](@ref) using regular string interpolation syntax.
 Note that interpolations are *evaluated* at LazyString construction time,
 but *printing* is delayed until the first access to the string.
 
+# Examples
+
+```
+julia> n = 5; str = lazy"n is \$n"
+"n is 5"
+
+julia> typeof(str)
+LazyString
+```
+
 !!! compat "Julia 1.8"
     `lazy"str"` requires Julia 1.8 or later.
 """