doc/radosgw: Fix length of section header underlines in oidc.rst

Set the length of the RST syntax underlining for section headers to be
as long as the section header text.
Also it seems common to indent the document title with one space at both
the beginning and the end so do that.

Signed-off-by: Ville Ojamo <[email protected]>

Author: bluikko

doc/radosgw/oidc.rst

@@ -1,6 +1,6 @@
-===============================
+================================
  OpenID Connect Provider in RGW
-===============================
+================================
 
 An entity describing the OpenID Connect Provider needs to be created in RGW, in order to establish trust between the two.
 
@@ -18,7 +18,7 @@ In order to invoke the REST admin APIs, a user with admin caps needs to be creat
 
 
 CreateOpenIDConnectProvider
----------------------------------
+---------------------------
 
 Create an OpenID Connect Provider entity in RGW
 
@@ -67,7 +67,7 @@ Example::
 
 
 GetOpenIDConnectProvider
----------------------------
+------------------------
 
 Gets information about an IDP.
 
@@ -120,7 +120,7 @@ Example::
     &ClientID=app-jee-jsp"
 
 RemoveClientIDFromOpenIDConnectProvider
-----------------------------------
+---------------------------------------
 
 Remove a client id from the list of existing client ids registered while creating an OpenIDConnectProvider.