Merge branch 'fix-textarea-expansion' into 'master'

Add textarea autoresize after comment

## What does this MR do?
Adds an autoresize after a comment is posted

## Are there points in the code the reviewer needs to double check?
Shouldn't be

## Why was this MR needed?
To keep the UI consistent (the same as if you were to refresh it)

## Screenshots (if relevant)
Before:
![IyCczzXfaf](/uploads/2229bad47e3f3821f1efaa6868a52025/IyCczzXfaf.gif)

After:
![E6O0kRBrJq](/uploads/4aec6b436ff172ba281c2c2a4481906d/E6O0kRBrJq.gif)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [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)

## What are the relevant issue numbers?
Closes #21667

See merge request !6152

1 files changed, 6 insertions, 1 deletions

diff --git a/app/assets/javascripts/notes.js b/app/assets/javascripts/notes.js
index d0d5cad813a..ebe9ff2b8c4 100644
--- a/app/assets/javascripts/notes.js
+++ b/app/assets/javascripts/notes.js
@@ -331,7 +331,12 @@
       form.find(".js-md-write-button").click();
       form.find(".js-note-text").val("").trigger("input");
       form.find(".js-note-text").data("autosave").reset();
-      return this.updateTargetButtons(e);
+
+      var event = document.createEvent('Event');
+      event.initEvent('autosize:update', true, false);
+      form.find('.js-autosize')[0].dispatchEvent(event);
+
+      this.updateTargetButtons(e);
     };
 
     Notes.prototype.reenableTargetFormSubmitButton = function() {