Update README.md

Update link to @ejmastnak tutorial page.

README.md

@@ -183,7 +183,7 @@ Note: instead of immediately reading the official documentation, you may want to
 Here are some LuaSnip videos and tutorials on the Web:
 - [Introductory](https://www.youtube.com/watch?v=Dn800rlPIho) and [advanced](https://www.youtube.com/watch?v=KtQZRAkgLqo) YouTube videos by the one and only [TJ DeVries](https://github.com/tjdevries). Unfortunately there were some breaking changes in LuaSnip since these videos were recorded:
   * Snippets are now added via [`ls.add_snippets`](https://github.com/L3MON4D3/LuaSnip/blob/master/DOC.md#adding-snippets) instead of with `ls.snippets = {}`
-- A [guide to writing snippets in Lua](https://www.ejmastnak.com/tutorials/vim-latex/luasnip.html) with LaTeX-themed GIFs and real-life examples by [@ejmastnak](https://github.com/ejmastnak)
+- A [guide to writing snippets in Lua](https://www.ejmastnak.com/tutorials/vim-latex/luasnip/) with LaTeX-themed GIFs and real-life examples by [@ejmastnak](https://github.com/ejmastnak)
 - A [collection of LuaSnip guides](https://evesdropper.dev/files/luasnip) by [@evesdropper](https://github.com/evesdropper), with most of them also in a LaTeX context
 - An introductory LuaSnip [video tutorial for beginners](https://www.youtube.com/watch?v=ub0REXjhpmk) by Ziontee113