fixing emails parse as mentions

[matteomorari]

I have add a new regex rule to catch emails before mentions to avoid false positive.

[mlomb]

Hey thanks for your contribution!

I'm going to get to this I promise. I have very little time available right now.

[mlomb]

Hey, as we all know there is no good regex for emails. I think a better solution is to force mentions to start with @, since emails do not start with @ (adding ^ to the mention regex). I did not realize this before.
Also if we add the tag email we should do something with it lol.

[mlomb]

Hey I reconsidered. I think is good to have a tag for emails, even if it does not catch every case, to avoid having emails marked as words.
I also force mentions to start with @ (nothing before), to disallow things like "abc@xyz" which are neither emails or mentions.

Thanks for your contribution, and sorry for the delay