update sponsoring status (#1685)

a history of sponsorships and contributors soon to be on the dedicated
page at nix.dev: NixOS/nix.dev#1117

---------

Co-authored-by: Thilo Billerbeck <[email protected]>

Author: fricklerhandwerk

src/content/teams/11_documentation.mdx

@@ -4,7 +4,7 @@ description: Works on improving learning experience and documentation.
 members:
   - name: Valentin Gagarin
     discourse: fricklerhandwerk
-    title: Nix documentarian, Sponsored by Antithesis via Tweag
+    title: Nix documentarian
   - name: wamirez
     discourse: wamirez
     title: