Minor documentation corrections.

Escape the space after "i.e." (or avoid using it altogether), add missing @ref.

Closes #16235.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_3_0_BRANCH@76471 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775