Fix regex to catch unknown bg or fg errors

Specify very magic, and make pattern a little stricter

Author: mmrwoods

autoload/fuzzyy/utils/popup.vim

@@ -89,7 +89,7 @@ def ResolveCursor()
             ctermfg: ctermfg,
             ctermbg: ctermbg
         }])
-    catch /(E419|E420|E453)/
+    catch /\v:(E419|E420|E453):/
         # foreground and/or background not known and used as ctermfg or ctermbg
         hlset([fallback])
     catch