V8: Accessibility improvements for page name entry

[RachBreeze]

This PR aims to fix 43, 69, 75, 81 from the from the A & AA accessibility issue list #5277

Creating a content item
When creating a new content type there is screen reader only text which says:
"Create" + content type name

The concept is that it create wors as per Microsoft Teams, here when a user creates a folder they see:

Editing a content item
When editing an existing content item there is screen reader only text which says
"Edit" + content name

Name label
The "name" text box also now now has a hidden label which is "content type name" + Name

Placeholder
The placeholder in the name textbox remains the same as prior to this change, as placeholder text provides guidance for many users, placeholder text is not a replacement for labels.

Class amends
This PR contains a sr-only class for displaying content for screen readers only. However there is nothing to stop the hidden text being displayed on the screen if HQ deem fit (subject to improved styling)

*Language amends
The language files now have accessibility specific place holders these have been added to en.xml and en_us.xml only

[MMasey]

Awesome work @RachBreeze. In regards to the .sr-only class, I've also create a .visually-hidden class in a separate PR https://github.com/umbraco/Umbraco-CMS/pull/5544/files. Just leaving a note here so that we can refactor them into one class when after they have both been merged in 😄

[RachBreeze]

@MMasey oops missed that sorry, more than happy to tidy up either now or when they're merged.

[MMasey]

@RachBreeze I think it's fine for now. Let's keep an eye on both of them and once the are both merged in we can all agree on a preferred solution and update accordingly 🙂

@nul800sebastiaan, @emmaburstow, @poornimanayar, @dawoe or @abjerner, could you add the accessibility label to this please. Thanks ❤️

[nul800sebastiaan]

Hi @RachBreeze - I think you accidentally mixed a lot of things up here. I was going to try to fix it but it also seems you deleted your fork?

Just a tip: you don't need to delete forks when you're done, 2 things to keep in mind:

1. Each PR you do should be a new branch made from v8/dev - that way you can work on and potentially update a PR at the same time as working on and updating another PR (by switching between branches).
2. When you switch back to dev/v8 you can update it from the central repository (the Umbraco HQ one) - this is described here: https://github.com/umbraco/Umbraco-CMS/blob/v8/dev/.github/CONTRIBUTING.md#keeping-your-umbraco-fork-in-sync-with-the-main-repository

Additionally, once you've synced v8/dev with the upstream (see link above) you could then switch to your PR branch and merge v8/dev into it, so you get the latest changes from us into your PR as well if needed.

I will close this PR for now, can I kindly ask you to resubmit it so that the work is not as completely tangled up as it is now?

Other than that I think it looks fine, well done!

[RachBreeze]

Cheers @nul800sebastiaan got slightly lost with the PR process here so thank you for your comments (I've done the same on my other outstanding PR. I will fix both)

[nul800sebastiaan]

No worries, it's confusing when you first get started, happy to help! Let me know if you have any questions.

[RachBreeze]

Hi @nul800sebastiaan just to let you know I've resubmitted this as #5760 cheers.