Add \fakeverb command for tabularray

[lvjr]

To ease the pain of writing verbatim commands (see https://github.com/lvjr/tabularray/issues/358), I will add \fakeverb command to codehigh package.

This command will remove the backslashes in the following control symbols before typesetting its content:

Input	Result	Catcode
\\	\	0
\{	{	1
\}	}	2
\#	#	6
\^	^	7
\		10
\%	%	14

The argument of \fakeverb command need to be enclosed with curly braces. Therefore it could be safely used inside tabularray tables and other LaTeX commands.

To make it a replacement for \verb command, we should not highlight the code inside this command by default.

[muzimuzhi]

Looks similar to \EscVerb from fvextra package.

[lvjr]

Looks similar to \EscVerb from fvextra package.

Yes, both are based on a similar idea. But not totally the same.