Don't use JSON code blocks, pagure.io doesn't play well with them

Signed-off-by: Petr Šabata <contyk@redhat.com>

README.rst

@@ -29,7 +29,7 @@ Module submission is done via posting the modulemd SCM URL.
 
     POST /rida/module-builds/
 
-.. code:: json
+::
 
     {
         "scmurl": "git://pkgs.fedoraproject.org/modules/foo.git/foo.yaml#f1d2d2f924e986ac86fdf7b36c94bcdf32beec15
@@ -41,7 +41,7 @@ The response, in case of a successful submission, would include the task ID.
 
     HTTP 201 Created
 
-.. code:: json
+::
 
     {
         id: 42
@@ -64,7 +64,7 @@ about the build task.
 
     HTTP 200 OK
 
-.. code:: json
+::
 
     {
         "id": 42,
@@ -94,7 +94,7 @@ The list of all tracked builds and their states can be obtained by querying the
 
     HTTP 200 OK
 
-.. code:: json
+::
 
     [
         {