Update Pattern edit_item string to Edit Block Pattern

[andrewserong]

Trac ticket: https://core.trac.wordpress.org/ticket/58716

Update the Pattern post type's edit_item label to be Edit Block Pattern instead of Edit Pattern to resolve an edge case in Google Chrome where Edit Pattern causes the browser to think that the page is in German, and therefore displays the translation popup.

After some digging, I couldn't work out why exactly Google Chrome thinks that the page is in German based on the string Edit Pattern, but my suspicion is that the server-rendered view of the block editor doesn't involve very many words, which could potentially contribute to it not recognising the language correctly (it appears to ignore the lang attribute set on the page). Updating to Edit Block Pattern appears to resolve the issue.

Before	After

Testing instructions

1. Go to http://localhost:8889/wp-admin/edit.php?post_type=wp_block
2. Edit an existing pattern (if you don't have any patterns, you'll need to add one first, then go back to the list and click Edit)
3. With this PR applied, Google Chrome should no longer prompt to translate the page when the editor loads

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This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

[ramonjd]

Before

After

This is a good compromise for a very strange bug. Thank you @andrewserong

[tellthemachines]

Thanks for the PR! Can confirm this fixes the issue for me.

[tellthemachines]

Committed in r56200 / 444bdf4.