Merge from origin/emacs-28

Merge from origin/emacs-28

160e62a23c Improve documentation and customization of 'blink-matching...
1100fffcd3 * lisp/erc/erc.el: Don't error if 'erc-loaddefs' does not ...
8865fc02ab Add 'erc-bug' command for reporting ERC bugs
5afa07919e Add 'erc-version' and use it to display ERC version consis...
bc941846d9 Small tweaks and improvements to etc/ERC-NEWS
30b5e0a514 Add NEWS items for changes to ERC since 5.3 to etc/ERC-NEWS
f7e6c199bf Clone the frame window configuration in 'clone-frame'
5f626488d8 * lisp/tool-bar.el (tool-bar-position): Doc fix.

# Conflicts:
#	etc/NEWS