Improved Telegram bot token rule regex and added more test cases

[toxyl]

Description:

At work we came across an edge-case where the Telegram bot token rule would match lots of XML schema definitions in which clm12345:AgencyIdentificationCodeContentType appears which happens be the exact same length the regex is looking for (A[a-zA-Z0-9_\-]{34}) prefixed with the right amount of digits ([0-9]{5,16}) . To fix it I've modified the regex to take boundaries into account and simplified a-zA-Z0-9 parts to a-z0-9 because the entire regex is already case insensitive ((?i)). Also added a few more test cases.

Checklist:

• Does your PR pass tests?
• Have you written new tests for your changes?
• Have you lint your code locally prior to submission?