Run "scripts/spell-check.sh" from the Squid tree root directory.
For details, see bug report 5021:
- https://bugs.squid-cache.org/show_bug.cgi?id=5021

 Changes to be committed:
	new file:   scripts/codespell-whitelist.txt
	new file:   scripts/spell-check.sh

(cherry picked from commit 0678534)

Addressed comments from the pull request squid-cache#565.

 Changes to be committed:
	modified:   scripts/spell-check.sh

doc/HTTP-codes.txt has a spelling error.

Still exclude doc/debug-sections.txt because it is generated.

Still exclude doc/*/*.txt because they are imported/foreign.

I could not find any more cases where \x was misinterpreted (for any x).

This is very useful when working on a small subset of files because
spell checking the whole tree takes a while:

    git diff $base --name-only | xargs ./scripts/spell-check.sh

The script cannot, technically, create "conflicts" (at least not in a
git sense of that word). The script might wipe out or corrupt unstaged
changes, and we want to protect users from that.

A very useful side effect of our protection is that any script changes
are very easy to _review_ using `git diff --word-diff`. Any developer
ought to review codespell changes. The script itself is probably not the
right place to document/discuss all that.