Add support for gleam, closes #655

Co-authored-by: Jeff Kreeftmeijer <jeffkreeftmeijer@gmail.com>

packages.yaml

@@ -5562,3 +5562,10 @@ filetypes:
   patterns:
   - pattern: '*.cjson,coc-settings.json,*.jsonc,.eslintrc.json,.babelrc,.jshintrc,.jslintrc,.mocharc.json,coffeelint.json,tsconfig.json,jsconfig.json'
     description: 'JSON with comments (https://komkom.github.io/)'
+---
+name: gleam
+remote: gleam-lang/gleam.vim
+filetypes:
+  - name: gleam
+    extensions:
+    - gleam