Remove zwsp characters from mdx files

[humtta]

While browsing the documentation, I noticed that the heading permalinks had a strange format, like:

https://www.jetify.com/docs/devbox/devbox-global#bash%E2%80%8B
https://www.jetify.com/docs/devbox/devbox-global#zsh%E2%80%8B
https://www.jetify.com/docs/devbox/devbox-global#fish%E2%80%8B

Whereas the expected format would be:

https://www.jetify.com/docs/devbox/devbox-global#bash
https://www.jetify.com/docs/devbox/devbox-global#zsh
https://www.jetify.com/docs/devbox/devbox-global#fish

While inspecting the contents of the docs/devbox/devbox-global/index.mdx file using the bat -A command, I noticed several occurrences of zero-width space (ZWSP) characters. For example:

80 │ ###·Bash[\u{200b}](#bash·"Direct·link·to·Bash")␊
90 │ ###·Zsh[\u{200b}](#zsh·"Direct·link·to·Zsh")␊
98 │ ###·Fish[\u{200b}](#fish·"Direct·link·to·Fish")␊

The Unicode character U+200B is encoded as the UTF-8 bytes E2 80 8B, which explains the %E2%80%8B suffix found in heading permalinks.

This PR removes all these ZWSP characters from the .mdx files. This was done with a script I wrote, using this command:

curl -fsSL https://gist.github.com/humtta/97a3193eaa779f55062057f28b0a78d8/raw/remove-zwsp.sh \
| bash -s -- **/*.mdx