Qmake: Highlight CLEAN_DEPS

Change-Id: I5450a4a099c705eea8c1fa110d3d3ad67bdf1ab4
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Reviewed-by: Daniel Teske <daniel.teske@digia.com>

src/plugins/qmakeprojectmanager/profilecompletionassist.cpp

@@ -38,6 +38,7 @@ using namespace TextEditor;
 
 static const char *const variableKeywords[] = {
     "CCFLAG",
+    "CLEAN_DEPS",
     "CONFIG",
     "DEFINES",
     "DEF_FILE",