Improve documentation for --enable=all flag

Author: preenu91

cli/cmdlineparser.cpp

@@ -1753,9 +1753,10 @@ void CmdLineParser::printHelp() const
         "                         further processing.\n"
         "    --enable=<id>        Enable additional checks. The available ids are:\n"
         "                          * all\n"
-        "                                  Enable all checks. It is recommended to only\n"
+        "                                  Enable all checks (warning, style, performance, portability, information). It is recommended to only\n"
         "                                  use --enable=all when the whole program is\n"
-        "                                  scanned, because this enables unusedFunction.\n"
+        "                                  scanned, because this enables extra checks such as unusedFunction that may produce\n"
+        "                                  many warnings. Example: cppcheck --enable = all file.cpp\n"
         "                          * warning\n"
         "                                  Enable warning messages\n"
         "                          * style\n"