Cleanup: Warning in debug console due to full stop in description

Fix warning generated due to the full-stop in the description message of
the property `use_auto_mask`

Property added in: rBa9cb66b856e80d0542a9ad3fec0b0fb47d28f805

source/blender/editors/sculpt_paint/sculpt_expand.c

@@ -2383,5 +2383,5 @@ void SCULPT_OT_expand(wmOperatorType *ot)
                              "use_auto_mask",
                              false,
                              "Auto Create",
-                             "Fill in mask if nothing is already masked.");
+                             "Fill in mask if nothing is already masked");
 }