Fix documentation link

Author: jamesfredley

plugin-core/docs/src/docs/index.tmpl

@@ -103,7 +103,7 @@ img {
 
 		<h2>User Guides - Grails 7 and beyond</h2>
         <ul>
-            <li><a href="/grails-spring-security/snapshot/core-plugin/guide/index.html">Core</a></li>
+            <li><a href="/grails-spring-security/7.0.x/core-plugin/guide/index.html">Core</a></li>
             <ul>
                 <li><a href="/grails-spring-security/7.0.x/acl-plugin/guide/index.html">ACL</a></li>
                 <li><a href="/grails-spring-security/7.0.x/cas-plugin/guide/index.html">CAS</a></li>