Merge from origin/emacs-26

Merge from origin/emacs-26

17ebb6e (origin/emacs-26) Use consistent function names in thread-tes...
1c86229 Fix format error in Faccept_process_output
b38b91a Lessen stack consumption in recursive read1
3eb4603 Match w32 paths in grep sans --null hits (Bug#32051)
5cc7c4b Fix previous make-network-process change
d6a1b69 Another documentation improvement in flyspell.el
9b49a8e Improve documentation of Flyspell
3744fda Provide feature 'threads
ef9025f Save the server alias on reconnect (Bug#29657)
db3874b Refer to "proper lists" instead of "true lists"
35e0305 Avoid turning on the global-minor-mode recursively
51bf4e4 Fix Bug#32085