Use Doxygen @deprecated tags for deprecated methods.

Instead of just mentioning that the methods are deprecated in the
documentation text, use the @deprecated tag for them to make it possible to
detect it in documentation-processing tools too.

Closes #16102.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76175 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Mark some deprecated wxGrid methods as deprecated in the documentation.

Point people to the new names of the deprecated methods.

Closes #16103.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76176 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775