Move type description of readOnly in its own paragraph

As is done for all other keywords.

Author: dlax

jsonschema-validation.xml

@@ -741,6 +741,9 @@
             </section>
 
             <section title='"readOnly"'>
+                <t>
+                    The value of this keyword MUST be a boolean.
+                </t>
                 <t>
                     If it has a value of boolean true, this keyword indicates that the value of the
                     instance is managed exclusively by the owning authority, and attempts by a user
@@ -752,7 +755,6 @@
                     number as read-only.
                 </t>
                 <t>
-                    The value of this keyword MUST be a boolean.
                     Omitting this keyword has the same behavior as a value of false.
                 </t>
             </section>