chore: import upstream snapshot with attribution

unauthenticated/js/highlight/languages/diff.min.js

@@ -0,0 +1,9 @@
+/*! `diff` grammar compiled for Highlight.js 11.7.0 */
+(()=>{var e=(()=>{"use strict";return e=>{const a=e.regex;return{name:"Diff",
+aliases:["patch"],contains:[{className:"meta",relevance:10,
+match:a.either(/^@@ +-\d+,\d+ +\+\d+,\d+ +@@/,/^\*\*\* +\d+,\d+ +\*\*\*\*$/,/^--- +\d+,\d+ +----$/)
+},{className:"comment",variants:[{
+begin:a.either(/Index: /,/^index/,/={3,}/,/^-{3}/,/^\*{3} /,/^\+{3}/,/^diff --git/),
+end:/$/},{match:/^\*{15}$/}]},{className:"addition",begin:/^\+/,end:/$/},{
+className:"deletion",begin:/^-/,end:/$/},{className:"addition",begin:/^!/,
+end:/$/}]}}})();hljs.registerLanguage("diff",e)})();