How do I turn on `\v` by default for Vim/Neovim regexes?

Question

After years of using Vim and then Neovim, I still find myself forgetting to escape parenthesis and the | character when I intend to use their special behaviour:

If I want to search for "this" or "that", this is incorrect:

/(this|that)/

Instead, I should have typed one of these two alternatives:

/\(this\|that\)/
/\v(this|that)/

I either have to backslash the (, |, and ) characters, or I have to use \v to enter "very magic" mode. From the docs:

\v	\m	\M	\V	matches
	'magic'	'nomagic'
$	$	$	\$	matches end-of-line
.	.	\.	\.	matches any character
*	*	\*	\*	any number of the previous atom
()	\(\)	\(\)	\(\)	grouping into an atom
|	\|	\|	\|	separating alternatives
\a	\a	\a	\a	alphabetic character
\\	\\	\\	\\	literal backslash
\.	\.	.	.	literal dot
\{	{	{	{	literal '{'
a	a	a	a	literal 'a'

How do I make \v the default mode, without having to type \v at the beginning of the regex?