add silent replies

[dozro]

Description

This PR adds the option to silently (without a mention) reply to a message.

Reply with mention:

Reply without mention:

How it looks on mobile:

Fixes #30

verification that it works
Screenshot taken in element

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings