QmlJS: Fix newly parsed document not being added to the snapshot copy.

This was the root cause of several issues with scoping and import
resolution. For instance, finding the components that instantiate a
component that's opened in the editor failed; leading to code
completion missing valid entries.

Reviewed-by: Erik Verbruggen
Reviewed-by: Roberto Raggi

src/plugins/qmljseditor/qmljseditor.cpp

@@ -2006,6 +2006,7 @@ SemanticInfo SemanticHighlighter::semanticInfo(const Source &source)
         doc = snapshot.documentFromSource(source.code, source.fileName);
         doc->setEditorRevision(source.revision);
         doc->parse();
+        snapshot.insert(doc);
     }
 
     SemanticInfo semanticInfo;