Log Message:
Update to 26.3

Changelog:
* Changes in Emacs 26.3

** New option 'help-enable-completion-auto-load'.
This allows disabling the new feature introduced in Emacs 26.1 which
loads files during completion of 'C-h f' and 'C-h v' according to
'definition-prefixes'.

** Emacs now supports the new Japanese Era name.
The newly assigned codepoint U+32FF was added to the Unicode Character
Database compiled into Emacs.