No changes, just refactor wxTextCtrl::SetStyle() in wxMSW.

No changes, just refactor wxTextCtrl::SetStyle() in wxMSW.

Split this overly long function into MSWSetCharFormat() and MSWSetParaFormat().

No real changes otherwise except for the use of PARAFORMAT instead of
PARAFORMAT2 if wxUSE_RICHEDIT2 is not set as it was certainly intended (but
the fact that nobody complained about this problem means that nobody must be
compiling without wxUSE_RICHEDIT2 by now so arguably we should just remove it
completely).

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@65564 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775