Change mention type from plaintext to special symbol like @

[MurzNN]

Very often I see messages like this, that prevent user mentions:

freijon: not soo big uhm I am not sure (please yell at me if I am wrong) Matthev (v = w for no mention), luké (é = e_) , Davé (é=e) and hm is Michael (t3chguy) also in the team?

I see here the problem with mentioning - it's too easy to do unneeded mention! For example, if I have name 'good', I will have many miss-mentions. Same here if I have popular name like "Bob" - I will receive mentions for all Bobs.

Will be good to change mention type from plaintext name to special symbol, for example via @ like in github, to minimize miss-mentions. Maybe do this optionally for not change old behaviour.

Using @ is very popular in other popular projects like Twitter, also now we have easy way to mention via click on user in Riot.

[MurzNN]

I think that plaintext mentions go to Matrix from IRC (like many other features, ex slash-commands), and this change will be badly accepted by IRC fans, but IRC is too old and the world is changing ;)

[lampholder]

I realise I have uncritically carried my IRC behaviour over to Riot/Matrix (and indeed spell people's names M4tthew, etc, to avoid binging).

We'd need to think about how we did this - right now Riot mentions are triggered on users' entering a display name or a mxid, and to my mind it feels peculiar to mention @mxid:matrix.org by typing @Display Name when @display Name looks a little bit like a mxid but isn't one :\

[MTRNord]

What about only doing a mention when sending pills? (of course it needs full client Support first)

[weeman1337]

I made the mistake choosing my given name as local part. Now I receive notifications for every "michael". This is so annoying :/ If not switching it completely it would already help if I can choose not to be notified on "substring match mentions".

[MadLittleMods]

Related to #19833

[t3chguy]

Duplicate of #8431