Improvements to English locale (#4453)

A few fixes and improvements.

Notable changes:

- `issues.ref_closing_from` now makes sense.
https://codeberg.org/attachments/c091cc42-f0bf-4a14-8e43-8c66ead5ef06

- `pulls.cmd_instruction_hint`: removed full stop.
https://codeberg.org/attachments/41fcf979-3a5b-48f8-9e60-bde0b06dd522

- `settings.wiki_rename_branch_main_desc`: fix based on change in stalled 3546 so the sentence makes sense.

- `find_file.go_to_file`: better describe what the button does
https://codeberg.org/attachments/e181e486-3376-446d-a994-bfe65c125a70

- `repos.unadopted.no_more`: it's also shown when there are no results, not when the server "ran out of results"
https://codeberg.org/attachments/9077cbc4-f9e7-4ee5-ad86-6cfff41fec37

- `security.txt`: rephrase to decrease brokenness of English.

- `translation_meta`: added a special string, can be used to trigger Weblate to create a PR, which is usable for debugging

Co-authors:
- https://codeberg.org/Cyborus
- https://codeberg.org/toolforger
- https://codeberg.org/woutput

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/4453
Reviewed-by: Earl Warren <earl-warren@noreply.codeberg.org>

public/.well-known/security.txt

@@ -1,6 +1,6 @@
 # This site is running a Forgejo instance.
 # Forgejo-related security problems should be reported to the Forgejo security team.
-# Site-related security problems should be reported to this site's admin.
+# Security problems related to this instance should be reported to its administration.
 Policy: https://codeberg.org/forgejo/forgejo/src/branch/forgejo/CONTRIBUTING.md
 Contact: mailto:security@forgejo.org
 Encryption: https://keys.openpgp.org/vks/v1/by-fingerprint/1B638BDF10969D627926B8D9F585D0F99E1FB56F