docs(template): Improve comment clarity in .gitignore

The comment in the template's `.gitignore` file has been updated from `# shared` to `# Globally Useful gitignores`.

This change provides a more descriptive and accurate explanation for the subsequent ignore patterns, enhancing the readability and maintainability of the file for future developers.

Author: liblaf

template/.gitignore

@@ -1,6 +1,6 @@
 # ref: <https://github.com/github/gitignore/blob/main/Python.gitignore>
 
-# shared
+# Globally Useful gitignores
 *.log
 *.log.*
 playground/