Fix spelling and punctuation errors in comments and documentation

Fix several occurrences of misspelling "trivial" as "trival"; use "from"
rather than "than"; add missing articles and commas.

Closes https://github.com/wxWidgets/wxWidgets/pull/874

interface/wx/hyperlink.h

@@ -18,7 +18,7 @@
 
     @beginEventTable{wxHyperlinkEvent}
     @event{EVT_HYPERLINK(id, func)}
-        User clicked on an hyperlink.
+        User clicked on a hyperlink.
     @endEventTable
 
     @library{wxadv}