Fix extra grammar issue in src/App

src/App/Document.h

@@ -515,7 +515,7 @@ protected:
     /// callback from the Document objects after property was changed
     void onChangedProperty(const DocumentObject *Who, const Property *What);
     /// helper which Recompute only this feature
-    /// @return 0 if succeed, 1 if failed, -1 if aborted by user.
+    /// @return 0 if succeeded, 1 if failed, -1 if aborted by user.
     int _recomputeFeature(DocumentObject* Feat);
     void _clearRedos();