richedit: Avoid rewrapping all text for isolated format changes.

richedit: Avoid rewrapping all text for isolated format changes.

When the character or paragraph format is changed the paragraph that
is changed is already marked to be rewrapped, so ME_MarkAllForWrapping
shouldn't be called.  Since ME_RewrapRepaint uses this function, it
shouldn't be called in these circumstances, since rewrapping all the
text can cause noticable delays when working with a lot of text.