fixing up the formatting on our editorconfig file (#16414)

.editorconfig

-# EditorConfig is awesome:
-http://EditorConfig.org
+# EditorConfig is awesome:http://EditorConfig.org
 
 # top-most EditorConfig file
 root = true
@@ -10,7 +9,7 @@ indent_style = space
 # (Please don't specify an indent_size here; that has too many unintended consequences.)
 
 # Code files
-[*.cs,*.csx,*.vb,*.vbx]
+[*.{cs,csx,vb,vbx}]
 indent_size = 4
 
 # Xml project files