Remove magic number and hard type enums in Geometry.h

- Remove currently present magic numbers
- Hard type enums, so magic numbers can no longer be introduced. We don't want people to introduce magic numbers.

src/Mod/TechDraw/Gui/TaskLineDecor.cpp

@@ -108,7 +108,7 @@ TechDraw::LineFormat *TaskLineDecor::getFormatAccessPtr(const std::string &edgeN
     BaseGeomPtr bg = m_partFeat->getEdge(edgeName);
     if (bg) {
         if (bg->getCosmetic()) {
-            if (bg->source() == SourceType::COSEDGE) {
+            if (bg->source() == SourceType::COSMETICEDGE) {
                 TechDraw::CosmeticEdge *ce = m_partFeat->getCosmeticEdgeBySelection(edgeName);
                 if (ce) {
                     return &ce->m_format;