Misc. documentation and source comment typo fixes

Found via `codespell -q 3 -L uint,od,objext,ba,cmo,bae,ans,struc,fo,clos,goin,upto,thru`
Revert changes in previous commit

Source/Doxygen/doxyparser.cxx

@@ -1294,7 +1294,7 @@ void DoxygenParser::tokenizeDoxygenComment(const std::string &doxygenComment, co
     string lastLine = lines[lines.size() - 1];
 
     if (trim(lastLine).empty()) {
-      lines.pop_back(); // remove trailing empy line
+      lines.pop_back(); // remove trailing empty line
     }
   }