Update CONTRIBUTING.md

Author: Ahmad-A0

CONTRIBUTING.md

@@ -17,8 +17,9 @@ If you would like to have collaborator permissions on the repo to merge your own
 ## Contributing Guidelines
 
 - **Match the casing of files and directories**
-  - For files, it's **`<language>/<problem-number>-Name-Of-Problem.<language-extension>`** (e.g. `java/1-Two-Sum.java`)
-  - *Note: This is subject to change in the future, as [described in this issue](https://github.com/neetcode-gh/leetcode/issues/457#issuecomment-1233558291)*
+  - For files, it's **`<language>/<problem-number>-name-of-problem.<language-extension>`** (e.g. `java/0001-two-sum.java`)
+    - Make sure the `problem-number` is formatted as four digits adding leading zeroes if necessary
+    - You can find the `name-of-problem` in the leetcode URL, e.g https://leetcode.com/problems/ _**two-sum**_ / 
 - **Give your PR a succinct and accurate title** (e.g. _"Create: 1-Two-Sum.py"_)
 - Prefer **one solution/change per PR** (not a hard and fast rule, but will typically make the review cycle shorter)
 - **Follow the** [PR template](./.github/pull_request_template.md) and add additional information when needed