Utils: Add comments to the PathChooser::Kind values

They are documented properly, but sometimes simpler to look here.

Change-Id: Ibe48a30bf0e7909c1cea1d414748a09962691615
Reviewed-by: Artem Sokolovskii <artem.sokolovskii@qt.io>

src/libs/utils/pathchooser.h

@@ -44,8 +44,8 @@ public:
     enum Kind {
         ExistingDirectory,
         Directory, // A directory, doesn't need to exist
-        File,
-        SaveFile,
+        File, // An existing file
+        SaveFile, // A file that does not need to exist
         ExistingCommand, // A command that must exist at the time of selection
         Command, // A command that may or may not exist at the time of selection (e.g. result of a build)
         Any