Add nf-dev-yaml to Cascadia Code glyphs

[mezdelex]

Description of the new feature/enhancement (with images if possible)

Recently, nf-dev-yaml was added to nvim-web-devicons for yaml extension, a widely adopted and used icon provider in Neovim. Cascadia Code is currently missing that icon, so it would be nice to have it.

Proposed technical implementation details (optional)

Currently we need to override it with our preferred one (the old one in my case), like so:

unless you want an empty block in your editor.