Rename Hyprnote to Char fully

[johnathanlaw]

There are a number of places Hyprnote are still referenced:

1. Brew Cask (fastrepl/hyprnote/hyprnote@nightly)
2. Package Name (https://char.com/download/)
3. Image in readme.md
4. 1510 occurrences across 401 files in the repository

I know name changes are hard but spotted the blog today and noticed it was five days ago, so figured I would make this issue to capture areas still needing actioned.

[yujonglee]

@johnathanlaw thanks for the report. we are trying to do this incrementally. Also working on new logo. Bear with us just for a bit!