doc/mgr/ceph_api: edit index.rst

Edit doc/mgr/ceph_api/index.rst as part of the project to determine
where the error is in ceph#62782 that
prevents the Jenkins tests from passing.

This is a change to one of twenty-five files in
ceph#62782, and this commit represents one
of what will be at least twenty-five other commits made to track this
error down.

Signed-off-by: Zac Dover <[email protected]>
(cherry picked from commit 5c17f22)

Author: zdover23

doc/mgr/ceph_api/index.rst

@@ -53,9 +53,11 @@ be obtained, and it may then be reused for subsequent requests. The
     { "token": "<redacted_token>", ...}
 
 The token obtained must be passed together with every API request in the
-``Authorization`` HTTP header::
+``Authorization`` HTTP header:
 
-  curl -H "Authorization: Bearer <token>" ...
+.. prompt:: bash $
+
+   curl -H "Authorization: Bearer <token>" ...
 
 Authentication and authorization can be further configured from the
 Ceph CLI, the Ceph-Dashboard UI and the Ceph API itself (please refer to