Likely the biggest change of the tailwind refactors. Only thing of note
is that `tw-flex-1` resolves to `flex: 1 1 0%` while our `gt-f1` was
`flex: 1 1 0`, I don't think it will make any difference. Commands I've
ran:

```sh
perl -p -i -e 's#gt-vm#tw-align-middle#g' web_src/js/**/* templates/**/* models/**/*
perl -p -i -e 's#gt-fw#tw-flex-wrap#g' web_src/js/**/* templates/**/* models/**/*
perl -p -i -e 's#gt-f1#tw-flex-1#g' web_src/js/**/* templates/**/* models/**/*
perl -p -i -e 's#gt-fc#tw-flex-col#g' web_src/js/**/* templates/**/* models/**/*
perl -p -i -e 's#gt-sb#tw-justify-between#g' web_src/js/**/* templates/**/* models/**/*
perl -p -i -e 's#gt-je#tw-justify-end#g' web_src/js/**/* templates/**/* models/**/*
perl -p -i -e 's#gt-jc#tw-justify-center#g' web_src/js/**/* templates/**/* models/**/*
perl -p -i -e 's#gt-ac#tw-content-center#g' web_src/js/**/* templates/**/* models/**/* tests/**/*
perl -p -i -e 's#gt-df#tw-flex#g' web_src/js/**/* templates/**/* models/**/* tests/**/*
perl -p -i -e 's#gt-dib#tw-inline-block#g' web_src/js/**/* templates/**/* models/**/* tests/**/*

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

Should look exactly like before for normal dividers. "Horizontal" ones
look better because they no longer use image backgrounds.

<img width="917" alt="Screenshot 2023-06-27 at 19 07 56"
src="https://github.com/go-gitea/gitea/assets/115237/d97d8dec-6859-44a8-85ba-e4549b4dd9df">

<img width="914" alt="Screenshot 2023-06-27 at 19 05 58"
src="https://github.com/go-gitea/gitea/assets/115237/8bf98544-2d82-4ebf-ac68-d6dc237bd6b2">

<img width="1246" alt="Screenshot 2023-06-27 at 19 00 42"
src="https://github.com/go-gitea/gitea/assets/115237/36a6bb21-6029-4f53-8bee-535f55c66fed">

<img width="344" alt="Screenshot 2023-06-27 at 18 58 15"
src="https://github.com/go-gitea/gitea/assets/115237/a9e70aee-8e6b-4ea1-9e93-19c9f96aec6e">
<img width="823" alt="Screenshot 2023-06-27 at 18 56 22"
src="https://github.com/go-gitea/gitea/assets/115237/e7a497cd-f262-4683-8872-23c3c8cce32f">

<img width="330" alt="Screenshot 2023-06-27 at 19 21 11"
src="https://github.com/go-gitea/gitea/assets/115237/42f24149-a655-4c7e-bd26-8ab52db6446b">

The code can be as simple as:

```html
<div class="flex-text-block">{{svg "octicon-alert"}} {{svg "octicon-x"}} text (block)</div>
<div><div class="flex-text-inline">{{svg "octicon-alert"}} {{svg "octicon-x"}} text</div> (inline)</div>
<div><button class="ui red button">{{svg "octicon-alert" 24}} {{svg "octicon-x" 24}} text</button></div>
```


![image](https://github.com/go-gitea/gitea/assets/2114189/1d3c10f1-0bc7-4c26-b236-bad537d5c465)

---------

Co-authored-by: Giteabot <teabot@gitea.io>

Fix regression of #22683 , it didn't pass all variables into
sub-template.

Close #23787

After the fix, all links and the form are correct.


![image](https://user-images.githubusercontent.com/2114189/228511037-580b5f5d-43e7-494f-9b66-89f9f908e208.png)


![image](https://user-images.githubusercontent.com/2114189/228510958-f960284a-101d-4b0e-b887-80033127898d.png)

This improves a lot of accessibility shortcomings.
Every possible instance of `<div class="button">` matching the command
`ag '<[^ab].*?class=.*?[" ]button[ "]' templates/ | grep -v 'dropdown'`
has been converted when possible.
divs with the `dropdown` class and their children were omitted as
1. more analysis must be conducted whether the dropdowns still work as
intended when they are a `button` instead of a `div`.
2. most dropdowns have `div`s as children. The HTML standard disallows
`div`s inside `button`s.
3. When a dropdown child that's part of the displayed text content is
converted to a `button`, the dropdown can be focused twice

Further changes include that all "gitea-managed" buttons with JS code
received an `e.preventDefault()` so that they don't accidentally submit
an underlying form, which would execute instead of cancel the action.
Lastly, some minor issues were fixed as well during the refactoring.

## Future improvements

As mentioned in
https://github.com/go-gitea/gitea/pull/23337#discussion_r1127277391,
`<a>`s without `href` attribute are not focusable.
They should later on be converted to `<button>`s.

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

As discussed in #22847 the helpers in helpers.less need to have a
separate prefix as they are causing conflicts with fomantic styles

This will allow us to have the `.gt-hidden { display:none !important; }`
style that is needed to for the reverted PR.

Of note in doing this I have noticed that there was already a conflict
with at least one chroma style which this PR now avoids.

I've also added in the `gt-hidden` style that matches the tailwind one
and switched the code that needed it to use that.

Signed-off-by: Andrew Thornton <art27@cantab.net>

---------

Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

Fix #21740.

Updated the Pull Request template so that the 'Update branch by merge'
button is visible for WIP PR's. Making the behaviour match a non WIP-PR.

Previous WIP page with changes pending on the branch:


![image](https://user-images.githubusercontent.com/1656302/215738307-e68a2f92-5ff8-4f48-a541-35ca81d1f1a4.png)

Updated UI adding the update button:


![image](https://user-images.githubusercontent.com/1656302/215737872-e0e9d712-b7aa-4b90-b7ed-6a92a14fc182.png)

## Notes

* have not removed the **$canAutoMerge** variable from the pull.tmpl on
this
[line](36dc11869d/templates/repo/issue/view_content/pull.tmpl (L131))
- doesn't appear to be used elsewhere but wasn't sure
* In order to avoid duplicating code corresponding UI code was added to
a new tmpl file, ```update_branch_by_merge.tmpl``` and is called in two
places from ```pull.tmpl```.

---------

Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>