Reorder of webpackConfig merge

[matthewturk]

The merge order of the different webpack config items currently pre-empts any
.html-catching rules.

References

• Prepend webpack rules with webpackConfig to catch .vue.html files #13032

Code changes

This changes the webpackConfig merge order to allow it to pre-empt the rule for
.html files. Putting the .html rule after the inclusion of webpackConfig
allows extension developers to override that rule, which is helpful for
situations such as VueJS extensions that use vue-loader. Previously,
vue-loader was testing if .vue.html would be caught by it. The order of
config merging prevented the .vue.html from being executed. This change
shouldn't affect any situations where .html was not being specified in the
webpackConfig override.

Closes #13032.

User-facing changes

This should not have any user-facing changes, and any developer-facing changes
should only arise in the case that a webpackConfig rule was specified and
not caught by the overridden configuration, which would arguably not be
intended behavior anyway.

Backwards-incompatible changes

There should be no changes.

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[fcollonval]

Thanks a lot for the PR @matthewturk

I have a suggestion to fix the linter error otherwise this is looking good.

You can add co-authors to a commit in GitHub with a special expression in the commit description: see documentation. But I'm find not being a co-author.

[fcollonval]

Don't worry about the license header error.

[matthewturk]

@fcollonval Thank you for the linter help! I thought I had correctly set it up in vscode, but ... looks like I hadn't. :)

[fcollonval]

Thanks @matthewturk

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Congrats on your first merged pull request in this project! 🎉

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[fcollonval]

@meeseeksdev please backport to 3.4.x

[lumberbot-app]

Owee, I'm MrMeeseeks, Look at me.

There seem to be a conflict, please backport manually. Here are approximate instructions:

1. Checkout backport branch and update it.

git checkout 3.4.x
git pull

2. Cherry pick the first parent branch of the this PR on top of the older branch:

git cherry-pick -x -m1 e3b441061391fe625c32b7136f6e1e685853c53b

3. You will likely have some merge/cherry-pick conflict here, fix them and commit:

git commit -am 'Backport PR #13040: Reorder of webpackConfig merge'

4. Push to a named branch:

git push YOURFORK 3.4.x:auto-backport-of-pr-13040-on-3.4.x

5. Create a PR against branch 3.4.x, I would have named this PR:

"Backport PR #13040 on branch 3.4.x (Reorder of webpackConfig merge)"

And apply the correct labels and milestones.

Congratulations — you did some good work! Hopefully your backport PR will be tested by the continuous integration and merged soon!

Remember to remove the Still Needs Manual Backport label once the PR gets merged.

If these instructions are inaccurate, feel free to suggest an improvement.