docs: add Muhammad Haris as a core contributor

PR-URL: #4973

Reviewed-by: Philipp Burckhardt <pburckhardt@outlook.com>
Signed-off-by: Athan Reines <kgryte@gmail.com>

Author: kgryte

CORE_CONTRIBUTORS.md

@@ -29,6 +29,7 @@ For information about the governance of the stdlib project, see [GOVERNANCE.md][
 -   [kgryte][athan-reines-github] - **Athan Reines** <[kgryte@gmail.com][athan-reines-email]> (he/him)
 -   [Planeshifter][philipp-burckhardt-github] - **Philipp Burckhardt** <[pburckhardt@outlook.com][philipp-burckhardt-email]> (he/him)
 -   [gunjjoshi][gunj-joshi-github] - **Gunj Joshi** <[gunjjoshi8372@gmail.com][gunj-joshi-email]> (he/him)
+-   [headlessNode][muhammad-haris-github] - **Muhammad Haris** <[harriskhan047@outlook.com][muhammad-haris-email]> (he/him)
 
 <details>
 <summary>Emeriti</summary>
@@ -57,6 +58,10 @@ For information about the governance of the stdlib project, see [GOVERNANCE.md][
 
 [gunj-joshi-email]: mailto:gunjjoshi8372@gmail.com
 
+[muhammad-haris-github]: https://github.com/headlessNode
+
+[muhammad-haris-email]: mailto:harriskhan047@outlook.com
+
 </section>
 
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