Escaped markdown should not be interpreted as shortcuts (like `@` and `#`)

Description

gitlab-flavoured markdown keeps adding new shortcuts to create terse, and easy to parse (for humans) textual representation with lots of cross-references. cool.

unfortunately this also means, that an ever growing number of special characters cannot be used for "normal" text anymore. this is especially true, for special characters that have a real-world usage that looks similar to the text-representation in GFM.

it also doesn't really help, that sometimes a reference will expand to a link (if the referenced item exists), and sometimes it stays "as is".

at the time of writing six (6!) characters (@#!$~%) are overloaded with special meaning (related to gitlab references), making them unusable for other things.

examples:

• #1 using a hash # followed by a number is often used to reference enumerations (in gitlab context this could mean enumerations within a given issue, rather than neighboring issues)

• ~5 the tilde ~ is a common abbreviation for approximately

• $10 prefixing a number with currency symbol is often used to denote amounts of money.

Proposal

it would be nice, if cross-references could be escaped easily.

e.g. i currently don't have a way to use "gitlab-ce#1" without making it either a link to issue#1 (and creating a back-reference there) or marking it as code (which has a distinct look and meaning).

even better than adding special characters to avoid creating gitlab references, would be have been a generic meta-escape character that starts a gitlab cross-reference. e.g. using #!5 (rather than !5) to reference MRs.

i don't see any obvious collision (currently #[^0-9] seems to be forbidden anyhow), but feel free to come up with something better.

Compatibility

obviously there might be compatibility issues with removing special meaning from a given character. but then, i guess you could keep the old behaviour for a while, documenting only the new behaviour (so it gets adopted), and allow the admin to convert all gitlab-references to the new scheme

References

github at least shares the PR and issue namespace, so you can use # to refer to either of them.