[Doc] Gitea in sub-path config document is incompatible with path escaping

[wxiaoguang]

Description

• Correct: https://docs.gitea.io/en-us/reverse-proxies/#nginx

• Buggy: https://docs.gitea.io/en-us/reverse-proxies/#nginx-with-a-sub-path

The ending slash shouldn't be used, because it causes nginx to unescape the path encodings, it breaks %2f in the path, breaks some Gitea git refs/paths and some Gitea package names/paths.

More details:

• 404 when clicking on composer package #20890 (comment)

Thanks to @ghnp5

[ghnp5]

Note that the "Buggy" section has a slash so that it will work for the sub-path.

If you remove the slash, all pages on Gitea will get a 404, because the "git/" sub-path is being passed to all URLs to Gitea.

To fix that, this hack is needed:

	location /git/ {
		# this hack prevents URL encoding, which can break the Packages area, for package names with slashes
		rewrite ^ $request_uri;
		rewrite ^/git(/.*) $1 break;
		return 400; # if the second rewrite won't match
		proxy_pass http://127.0.0.1:1234$uri;