Merge from emacs-26

Merge from emacs-26

463f96b481 * doc/lispref/searching.texi: Document regexp repetition l...
08a6195571 ; test/README: Document TEST_LOAD_EL parameter.
7bbea90b1a * src/syntax.c (char-syntax): Warn about ignoring text pro...
50fcbb5f61 ; * src/process.c (Fprocess_contact): Fix docstring typo.
81ae9c8c05 Load mm-util as needed for url-file and url-data (Bug#30258)
5a1ee67ae1 Another minor copyedit in the manual's "Scroll Bars"
226a651e9e Minor fix in documentation of 'equal'
b26786c8d9 * lisp/dired-x.el (dired-guess-shell-alist-user): Doc fix....
5699a824f0 Minor rewording in Emacs manual's "Help Mode" node
f35ff0156e Fixes for Emacs manual in frames.texi
6cd4e8dcc5 * doc/misc/cl.texi (Efficiency Concerns): Fix 2012-10-27 t...
1412cf3edd Fix a few issues with latest GTK scaling changes
59db8dca03 Use scaled coordinates when calling into GTK
2892f05792 Scale monitor dimensions obtained from GTK