Add a note about redirection rule to precise how regex/replacement work.

[nmengin]

Description

The mechanism used to redirect URLs between entrypoints does not use the fields regex and replacement, which are overriden if defined.

The PR adds precision about this point in documentation.

[dtomcej]

Instead of !!! can we use bolding or some sort of markdown based notification ;)

[ldez]

We use !!! as Markdown syntax, it's related to our new documentation theme : http://squidfunk.github.io/mkdocs-material/extensions/admonition/

[dtomcej]

So sorry about that, didn't know!

[dtomcej]

I would use the wording:

Please note that regex and replacement do not have to be set in the redirect structure if an entrypoint is defined for the redirection (they will not be used in this case)

[dtomcej]

I would use the wording:

Please note, if you have regex and replacement used to rewrite a URL, ensure that you do not have entrypoint defined in the redirect structure, or they will be ignored (as noted above).

[dtomcej]

LGTM

[ldez]

LGTM

[juliens]

LGTM