[PartDesign]: Sort sketches in Attach sketch tool alphabetically

The order of sketches in sketch attaching tool is now determined
by the order in which they were added to document.
Sorting them alphabetically makes IMHO much easier to find a sketch
by user, compared to current state, especially in large and complex
projects with lot of sketches. Of cuser thix expects the user
use sensible names for the sketches.

src/Mod/Sketcher/Gui/Command.cpp

@@ -605,6 +605,9 @@ void CmdSketcherMapSketch::activated(int iMsg)
 
             return;
         }
+        std::sort(sketches.begin(), sketches.end(), [](const auto &a, const auto &b) {
+            return QString::fromUtf8(a->Label.getValue()) < QString::fromUtf8(b->Label.getValue());
+        });
 
         bool ok;
         QStringList items;