Merge branch 'fix-button-missing-type' into 'master'

Fix button missing type

## What does this MR do?
Adds the `type` attribute to `<button>` 
## Are there points in the code the reviewer needs to double check?
Shouldn't be

## Why was this MR needed?
So that bootlint would stop giving warnings on the issue thread page and the merge request thread page

## What are the relevant issue numbers?
#20715

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5718

CHANGELOG

@@ -111,6 +111,7 @@ v 8.11.0 (unreleased)
   - Fix diff comments inverted toggle bug (ClemMakesApps)
   - Multiple trigger variables show in separate lines (Katarzyna Kobierska Ula Budziszewska)
   - Profile requests when a header is passed
+  - Fix button missing type (ClemMakesApps)
   - Avoid calculation of line_code and position for _line partial when showing diff notes on discussion tab.
   - Speedup DiffNote#active? on discussions, preloading noteables and avoid touching git repository to return diff_refs when possible
   - Add commit stats in commit api. !5517 (dixpac)

app/views/projects/issues/show.html.haml

@@ -22,7 +22,7 @@
   - if can?(current_user, :create_issue, @project) || can?(current_user, :update_issue, @issue)
     .issuable-actions
       .clearfix.issue-btn-group.dropdown
-        %button.btn.btn-default.pull-left.hidden-md.hidden-lg{ data: { toggle: "dropdown" } }
+        %button.btn.btn-default.pull-left.hidden-md.hidden-lg{ type: "button", data: { toggle: "dropdown" } }
           %span.caret
           Options
         .dropdown-menu.dropdown-menu-align-right.hidden-lg

app/views/projects/merge_requests/show/_mr_title.html.haml

@@ -14,7 +14,7 @@
   - if can?(current_user, :update_merge_request, @merge_request)
     .issuable-actions
       .clearfix.issue-btn-group.dropdown
-        %button.btn.btn-default.pull-left.hidden-md.hidden-lg{ data: { toggle: "dropdown" } }
+        %button.btn.btn-default.pull-left.hidden-md.hidden-lg{ type: "button", data: { toggle: "dropdown" } }
           %span.caret
           Options
         .dropdown-menu.dropdown-menu-align-right.hidden-lg