ProjectPart: Allow for line/column information in project file

Keep this information separate so that plugins using the information
do not need to start parsing the project file.

Change-Id: Ibecf431de1b12bbe820c6f8f9c986cffeb4972d2
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: Nikolai Kosjar <nikolai.kosjar@qt.io>

src/plugins/qbsprojectmanager/qbsproject.cpp

@@ -996,7 +996,8 @@ void QbsProject::updateCppCodeModel()
             rpp.setHeaderPaths(grpHeaderPaths);
 
             rpp.setDisplayName(grp.name());
-            rpp.setProjectFile(groupLocationToProjectFile(grp.location()));
+            rpp.setProjectFile(grp.location().filePath(),
+                               grp.location().line(), grp.location().column());
 
             QHash<QString, qbs::ArtifactData> filePathToSourceArtifact;
             bool hasCFiles = false;