Fix rendering of inline literal with withespaces (#4301)

Fix wrong rendering of an inline literal with whitespaces.
Use `:literal` as workaround, with esacpes whitespace `\ ` and added
non-break-whitespace chars (U+00A0).
diff --git a/src/docs/src/api/server/authn.rst b/src/docs/src/api/server/authn.rst
index b4a4806..bffe0bf 100644
--- a/src/docs/src/api/server/authn.rst
+++ b/src/docs/src/api/server/authn.rst
@@ -426,7 +426,7 @@
 should ensure that all nodes of your cluster have the same list.
 
 Since version 3.3 it's possible to use ``=`` in parameter names, but only when
-the parameter and value are separated `` = ``, i.e. the equal sign is
+the parameter and value are separated :literal:`\  = \ `, i.e. the equal sign is
 surrounded by at least one space on each side. This might be useful in the
 ``[jwt_keys]`` section where base64 encoded keys may contain the ``=``
 character.