Merge from origin/emacs-26

Merge from origin/emacs-26

2c0cfa6455 * ChangeLog.3: Update
4387bb44ae Update authors
bce51bd6f7 * lisp/gnus/message.el (message-do-auto-fill): Prevent do-...
bd2a2a1e84 Improve documentation of etags
7ba75b9637 Teach etags new interpreters for some languages
1f7f03742d * lisp/emacs-lisp/generator.el (iter-defun): Add 'doc-stri...
dbb4aac212 * lisp/emacs-lisp/syntax.el (syntax-propertize): Fix bug#2...
80463a43da Improve documentation of fill-separate-heterogeneous-words...
4bd2416d55 Fix documentation of some x-* functions
9c2b11484f Inherit query-on-exit flag to stderr process (Bug#30031)
3efb1e7def Fix Bug#30057
a9b884c60f Tag some unstable tests, and skip by default (bug#24503)

# Conflicts:
#	test/lisp/emacs-lisp/eieio-tests/eieio-tests.el