docs: update contributing.md to reflect current labels (#19440)

CONTRIBUTING.md

@@ -15,12 +15,14 @@ that include your webpack.config.js, relevant files, and the full error message
 
 **If you have discovered a bug or have a feature suggestion, please [create an issue on GitHub](https://github.com/webpack/webpack/issues/new).**
 
-Do you want to fix an issue? Look at the issues with a tag of [X5: work required (PR / Help Wanted)](https://github.com/webpack/webpack/labels/X5%3A%20work%20required%20%28PR%20%2F%20Help%20Wanted%29). Each issue should be tagged with a difficulty tag -
+Do you want to fix an issue? Look at the issues with a tag of [X5: work required (PR / Help Wanted)](https://github.com/webpack/webpack/labels/X5%3A%20work%20required%20%28PR%20%2F%20Help%20Wanted%29). Here are some of the key labels you may encounter:
 
-- D0: My First Commit (Contribution Difficulty)
-- D1: Easy (Contribution Difficulty)
-- D2: Medium (Contribution Difficulty)
-- D3: Hard (Contribution Difficulty)
+- **bug**: An unexpected problem or unintended behavior.
+- **enhancement**: A suggestion for a new feature or improvement.
+- **question**: Requests for clarification or more information.
+- **documentation**: Issues related to improving or adding documentation.
+
+> **Note:** Previous references to labels such as `D0: My First Commit`, `D1: Easy`, `D2: Medium`, and `D3: Hard` have been removed as these are not currently in use. If you would like to see difficulty labels added, please open a suggestion or discuss with maintainers.
 
 ## Contributing to the webpack ecosystem