[Canvas][Docs] Merge Canvas function references (elastic#38300)

* Synced up docs with function defs

* Updated docs with changes from PR elastic#37305

* Merged canvas function ref into a single doc

* Fixed arg order

* Fixed typo

* Added alphabet links

* Added alphabet headers

* Removed B header

* Added missing args from

* Added edits from PR elastic#37614

* Updated containerStyle

* Removed metafields. ESSQL doesn't support retrieving metafields

* Edits to function copy

* More edits

* More edits

* Final round of edits

* Fixed i18n errors

* Addressing feedback

* Fixed jest test

* Fixed missing import

* Fixed i18n error

* Restored metaFields arg in esdocs

* Extracted i18n string constants

* Fixed i18n errors

* Updated translation files