fix(tex): specify filetype for <localleader>l (#4905)

## Description

Specify the filetype for the keymap `<localleader>l` to ensure that this
keybinding group only appears when editing TeX files.

## Related Issue(s)

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  If this PR fixes any issues, please link to the issue here.
  - Fixes #<issue_number>
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## Screenshots

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## Checklist

- [x] I've read the
[CONTRIBUTING](https://github.com/LazyVim/LazyVim/blob/main/CONTRIBUTING.md)
guidelines.

lua/lazyvim/plugins/extras/lang/tex.lua

@@ -30,7 +30,7 @@ return {
       vim.g.vimtex_quickfix_method = vim.fn.executable("pplatex") == 1 and "pplatex" or "latexlog"
     end,
     keys = {
-      { "<localLeader>l", "", desc = "+vimtex" },
+      { "<localLeader>l", "", desc = "+vimtex", ft = "tex" },
     },
   },