Add in documentation on setting and retrieving contact settings using…

Co-Authored-By: Tim Otten <totten@civicrm.org>

Update explorer url

Add in documentation on setting and retrieving contact settings using the Civi:: facade and also add in note about the deprecation of the ::setItem function

Fix indentation of code block in hook_civicrm_permission

Fixed typo

Incorporate Abandoned Extensions process

Typo fix & SetCheckPermissions example.

tools/issue-tracking.md - Update guidance on Gitlab labels

Add use statement for definition - hopefully people will know that go…

__Before__: The documentation explains ~5 common labels.  Gitlab actually has ~50
labels.

__After__: The documentation explains ~3 important labels and ~4 *prefixes*.
Each prefix is given with a definition and example, and there are links
to the full lists.

__Comment__: The link goes to https://lab.civicrm.org/dev/core/-/labels
though arguably https://lab.civicrm.org/groups/dev/-/labels might be better.
However, there a dozen or so labels which (rightly or wrongly) only show up
in `dev/core`, so `dev/core` gives the more comprehensive listing.

Add link to Abandoned Extensions page/info.

update hook_civicrm_export signature

Further improvements to l10n format in hook_civicrm_permission docume…

Further clarification of financial items

improve suggestions re custom reports

Edits to APIv4 section

Document regen.sh

Formatting improvements and add code comments on Order API + fix broken URL

Co-Authored-By: Mikey O'Toole <mikey@mjco.uk>

update my repo from upstream master

Document BuildKit EoL Policy

provided best practice advice on report extension creation