Merge from origin/emacs-26

Merge from origin/emacs-26

b94d767 (origin/emacs-26) Minor copyedits in last manual change
73508e6 Improve documentation of face numbers
bf235ce * doc/emacs/custom.texi (Authentication): Refer to the "Help ...
ceccb3c New node Authentication in the Emacs manual
9078f34 Fix a loop in c-fl-decl-start.  This fixes bug #34186.
a177fe7 Fix LaTeX output of month and day from cal-tex.el
90177d7 Avoid elisp crash for OpenPGP User IDs with no e-mail address
68e55a0 image-mode: Do not use default scaling (bug#33990)
b6c762a create-image: Expand documentation (bug#33990)
928d342 Improve documentation of 'isearch-filter-predicate'
9034dd6 Fix cursor column positioning on Grep hits

# Conflicts:
#	doc/emacs/custom.texi