add CODEOWNERS for docs/sphinx (#216)

.github/CODEOWNERS

@@ -1,7 +1,8 @@
 * @ROCm/rocprof-sys @jrmadsen 
 
 # Documentation files
-docs/* @ROCm/rocm-documentation
+docs/** @ROCm/rocm-documentation
 *.md @ROCm/rocm-documentation
 *.rst @ROCm/rocm-documentation
 .readthedocs.yaml @ROCm/rocm-documentation
+docs/sphinx/* @samjwu