Add flexbox to project header
## What does this MR do?
Adds flexbox to project header to keep components vertically centered regardless of description presence/length
## What are the relevant issue numbers?
Closes #18080
## Screenshots (if relevant)


See merge request !4417
Notifications dropdown on project page now has descriptions
## What does this MR do?
Adds descriptions to the notification settings dropdown on project pages. Also changed the order of them to make more sense.
## What are the relevant issue numbers?
Part of #12758
## Screenshots (if relevant)

See merge request !4374
Sub navigation
## What does this MR do?
Styles sub nav
cc @dzaporozhets @skyruler @jschatz1
## What are the relevant issue numbers?
#18058 and #17983
## Screenshots (if relevant)


See merge request !4468
Add padding to bottom of wiki page, fix#12921.
## What does this MR do?
Adds padding to the bottom of the wiki page so it's not right up against the edge of the browser window.
## What are the relevant issue numbers?
#12921
## Screenshots (if relevant)
Before:

After:

cc: @jschatz1
See merge request !4490
Shows the edit comment button on mobile
## What does this MR do?
Shows the edit comment button on mobile.
## What are the relevant issue numbers?
Closes#17214
## Screenshots (if relevant)

See merge request !4402
Add confidential issue notice in comment box.
## What does this MR do?
Adds a warning about confidential issues to the comment field when the issue is confidential.
## Are there points in the code the reviewer needs to double check?
I don't think so.
## Why was this MR needed?
It wasn't clear to users that they were commenting on a confidential issue, this makes it more explicit.
## What are the relevant issue numbers?
Fixes#15288
## Screenshots (if relevant)
This is what it looks like at various screen sizes:



cc: @jschatz1 @dzaporozhets
See merge request !4473
* commit 'ca3c5c295ed653b483fe81c3918ffe60f46666b9':
Let contributors know where to start
Ensure branch cleanup regardless of whether the import process succeeds
Fix failing todo tests
Reorder the todos because the use of the project finder attempts to order them differently
Update target todo test to use a public project
Use the project finder in the todos finder to limit todos to just ones within projects you have access to.
Move filtering todos by projects not pending deletion into a scope on the todo model
Reduce the filters on the todos joins project query by being explicit about the join
Ensure we don't show TODOS for projects pending delete
Fix deprecation warnings in spec/services/issues/bulk_update_service_spec.rb
Remove unused Issuable#is_assigned? method
fixup! Don't allow merges with new commits
fixup! Add `sha` parameter to MR accept API
Reduce Namespace queries in UserReferenceFilter
Added ReferenceFilter#nodes
Returning enums in ReferenceFilter#each_node
Don't allow merges with new commits
Add `sha` parameter to MR accept API
Resolve "SHA parameter in accept merge request API"
Add a `sha` parameter to the MR merge API, which must match the source SHA for the branch to be merged.
Also add the same parameter to the UI:

@DouweM and I discussed adding some smart feature to that, like updating the source SHA on navigating to the diff tab, but for now it will just require a refresh 😃Closes#14139.
See merge request !4414