An attempt at porting the snippets that Gilles Castel (https://github.com/gillescastel/) had in his latex-snippets repository in Luasnip lua syntax. I could not port all of his snippets, due to a lack of experience with Ultisnips and Luasnips at my part.
This branch of this repository is meant to have snippets written in Luasnip that contain the exact same functionality that his snippets written in Ultisnips syntax had.
Personally, when porting these snippets, I felt that a) Castel may have made some mistakes when writing these snippets, i.e. that some of these snippets were redundant, and b) that I had some ideas that could improve upon his snippets, i.e. adding conditions to prevent some snippets from triggering outside of math environments. Despite this, I didn't want to litter this with my own ideas--whose motivations are subjective--so I decided to port all of the snippets exactly as they were. I want this branch of this repository to provide a base for anyone inspired by Castel's snippets to take his exact snippets with their exact purpose, only now in Luasnip syntax, and change them for themselves as they see fit.