Currently, in order to give the nice prompt for missing packages, we
look for any `using`/`import` statements in the AST before evaluation.
However, this misses any `using` statements introduced by macros:

```
julia> using Pkg

julia> using BenchmarkTools
 │ Package BenchmarkTools not found, but a package named BenchmarkTools is
 │ available from a registry.
 │ Install package?
 │   (@v1.11) pkg> add BenchmarkTools
 └ (y/n/o) [y]: n
ERROR: ArgumentError: Package BenchmarkTools not found in current path.
- Run `import Pkg; Pkg.add("BenchmarkTools")` to install the BenchmarkTools package.
Stacktrace:
 [1] macro expansion
   @ Base ./loading.jl:1781 [inlined]
 [2] macro expansion
   @ Base ./lock.jl:267 [inlined]
 [3] __require(into::Module, mod::Symbol)
   @ Base ./loading.jl:1762
 [4] #invoke_in_world#3
   @ Base ./essentials.jl:963 [inlined]
 [5] invoke_in_world
   @ Base ./essentials.jl:960 [inlined]
 [6] require(into::Module, mod::Symbol)
   @ Base ./loading.jl:1755

julia> macro foo()
       :(using BenchmarkTools)
       end
@foo (macro with 1 method)

julia> @foo
ERROR: ArgumentError: Package BenchmarkTools not found in current path.
- Run `import Pkg; Pkg.add("BenchmarkTools")` to install the BenchmarkTools package.
Stacktrace:
 [1] macro expansion
   @ Base ./loading.jl:1781 [inlined]
 [2] macro expansion
   @ Base ./lock.jl:267 [inlined]
 [3] __require(into::Module, mod::Symbol)
   @ Base ./loading.jl:1762
 [4] #invoke_in_world#3
   @ Base ./essentials.jl:963 [inlined]
 [5] invoke_in_world
   @ Base ./essentials.jl:960 [inlined]
 [6] require(into::Module, mod::Symbol)
   @ Base ./loading.jl:1755
 [7] top-level scope
   @ REPL[4]:1
```

Generally, it doesn't matter, but embedded DSLs may want to do this kind
of thing, so we might as well try to support it.