Sketcher: new icons for two existing commands

New SVG icons, `Sketcher_DeleteConstraints`, `Sketcher_DeleteGeometry`
for two commands which previously used the very simple icon
`Element_SelectionTypeInvalid` (a single red X).

These icons clarify that the commands are used to delete
the constraints and the geometry, respectively.

src/Mod/Sketcher/Gui/CommandSketcherTools.cpp

@@ -1944,7 +1944,7 @@ CmdSketcherDeleteAllGeometry::CmdSketcherDeleteAllGeometry()
     sToolTipText    = QT_TR_NOOP("Deletes all the geometry and constraints but external geometry");
     sWhatsThis      = "Sketcher_DeleteAllGeometry";
     sStatusTip      = sToolTipText;
-    sPixmap         = "Sketcher_Element_SelectionTypeInvalid";
+    sPixmap         = "Sketcher_DeleteGeometry";
     sAccel          = "";
     eType           = ForEdit;
 }
@@ -2007,7 +2007,7 @@ CmdSketcherDeleteAllConstraints::CmdSketcherDeleteAllConstraints()
     sToolTipText    = QT_TR_NOOP("Deletes all the constraints");
     sWhatsThis      = "Sketcher_DeleteAllConstraints";
     sStatusTip      = sToolTipText;
-    sPixmap         = "Sketcher_Element_SelectionTypeInvalid";
+    sPixmap         = "Sketcher_DeleteConstraints";
     sAccel          = "";
     eType           = ForEdit;
 }

src/Mod/Sketcher/Gui/Resources/Sketcher.qrc

@@ -239,6 +239,8 @@
         <file>icons/tools/Sketcher_CloseShape.svg</file>
         <file>icons/tools/Sketcher_ConnectLines.svg</file>
         <file>icons/tools/Sketcher_Copy.svg</file>
+        <file>icons/tools/Sketcher_DeleteConstraints.svg</file>
+        <file>icons/tools/Sketcher_DeleteGeometry.svg</file>
         <file>icons/tools/Sketcher_Move.svg</file>
         <file>icons/tools/Sketcher_RectangularArray.svg</file>
         <file>icons/tools/Sketcher_SelectConflictingConstraints.svg</file>