Add width to caret to rid ourselves of the shift

Add CHANGELOG

uses fa-fw from font awesome instead of using declaring fix width explicitly

moves changelog entry under 8.14

rebased with master

CHANGELOG.md

@@ -6,6 +6,7 @@ entry.
 - Show correct environment log in admin/logs (@duk3luk3 !7191)
 - Fix Milestone dropdown not stay selected for `Upcoming` and `No Milestone` option !7117
+- Diff collapse won't shift when collapsing.
 - Backups do not fail anymore when using tar on annex and custom_hooks only. !5814
 - Adds user project membership expired event to clarify why user was removed (Callum Dryden)
 - Trim leading and trailing whitespace on project_path (Linus Thiel)

app/views/projects/diffs/_file_header.html.haml

-%i.fa.diff-toggle-caret
+%i.fa.diff-toggle-caret.fa-fw
 - if defined?(blob) && blob && diff_file.submodule?
   %span
     = icon('archive fw')