STYLE: Add somme comments

Source/CTest/cmCTestCoverageHandler.h

@@ -56,9 +56,14 @@ private:
   bool StartCoverageLogFile(cmGeneratedFileStream& ostr, int logFileCount);
   void EndCoverageLogFile(cmGeneratedFileStream& ostr, int logFileCount);
 
+  //! Handle coverage using GCC's GCov
   int HandleGCovCoverage(cmCTestCoverageHandlerContainer* cont);
+
+  //! Handle Python coverage using Python's Trace.py
   int HandleTracePyCoverage(cmCTestCoverageHandlerContainer* cont);
 
+  // Find the source file based on the source and build tree. This is used for
+  // Trace.py mode, since that one does not tell us where the source file is.
   std::string FindFile(cmCTestCoverageHandlerContainer* cont,
     std::string fileName);