chore: bump soupsieve from 2.6 to 2.8.4 in /docs

Bumps [soupsieve](https://github.com/facelessuser/soupsieve) from 2.6 to 2.8.4.
- [Release notes](https://github.com/facelessuser/soupsieve/releases)
- [Commits](facelessuser/soupsieve@2.6...2.8.4)

---
updated-dependencies:
- dependency-name: soupsieve
  dependency-version: 2.8.4
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

docs/requirements.txt

@@ -246,9 +246,9 @@ smmap==5.0.2 \
     --hash=sha256:26ea65a03958fa0c8a1c7e8c7a58fdc77221b8910f6be2131affade476898ad5 \
     --hash=sha256:b30115f0def7d7531d22a0fb6502488d879e75b260a9db4d0819cfb25403af5e
     # via gitdb
-soupsieve==2.6 \
-    --hash=sha256:e2e68417777af359ec65daac1057404a3c8a5455bb8abc36f1a9866ab1a51abb \
-    --hash=sha256:e72c4ff06e4fb6e4b5a9f0f55fe6e81514581fca1515028625d0f299c602ccc9
+soupsieve==2.8.4 \
+    --hash=sha256:e121fd02e975c695e4e9e8774a5ee35d74714b59307868dcc5319ad2d9e3328e \
+    --hash=sha256:e7e6b0769c8f51ed59acab6e994b00621096cfb1c640a7509295987388fbaf65
     # via beautifulsoup4
 super-collections==0.5.3 \
     --hash=sha256:907d35b25dc4070910e8254bf2f5c928348af1cf8a1f1e8259e06c666e902cff \