Move a comment from a header to relevant docs

QProcess::FailedToStart had a //### comment which looked distractingly
like it wanted some action, but it was really just documenting the
enum member. Removed the comment and updated the doc to reflect the
one fragment of information that the comment added.

Task-number: QTBUG-85700
Change-Id: Ibe11b91a998751ee9cdd3018cc6a3d8f3ab30eea
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>

src/corelib/io/qprocess.cpp

@@ -673,7 +673,7 @@ void QProcessPrivate::Channel::clear()
 
     \value FailedToStart The process failed to start. Either the
     invoked program is missing, or you may have insufficient
-    permissions to invoke the program.
+    permissions or resources to invoke the program.
 
     \value Crashed The process crashed some time after starting
     successfully.

src/corelib/io/qprocess.h

@@ -112,7 +112,7 @@ class Q_CORE_EXPORT QProcess : public QIODevice
     Q_OBJECT
 public:
     enum ProcessError {
-        FailedToStart, //### file not found, resource error
+        FailedToStart,
         Crashed,
         Timedout,
         ReadError,