enh: add user-select none to filename badge (#346)

Add `user-select: none` on badge and icon to make sure
they are ignored when selecting the filename, so that when
double-clicking on a filename we now can select the same string
that this feature copies.

![image](https://user-images.githubusercontent.com/23088305/79253933-f5d43f80-7e51-11ea-9c57-08fa5d671e71.png)

`frontend/src/helpers/authorization/abilityActions.js ` (copied)

Closes #344

src/insert-copy-filename/insert-copy-filename.css

@@ -0,0 +1,4 @@
+/* fix ability to select filename correctly in a PR, removing Icon from being selected */
+.filename span {
+    user-select: none;
+}

src/insert-copy-filename/insert-copy-filename.js

@@ -3,6 +3,8 @@
 
 import { h } from 'dom-chef'
 
+import './insert-copy-filename.css'
+
 function onClick() {
     const diff: HTMLElement = ((this: HTMLButtonElement).closest(
         '.bb-udiff'