`@testitem` has no docstring

```julia
help?> @testitem
  No documentation found for public symbol.

  TestItems.@testitem is a macro.

  # 1 method for macro "@testitem" from TestItems:
   [1] var"@testitem"(__source__::LineNumberNode, __module__::Module, ex...)
       @ ~/.julia/packages/TestItems/A90xH/src/TestItems.jl:5