Fix typo and trailing dot (#4643)

Author: xabbuh

language/oop5/property-hooks.xml

@@ -510,8 +510,8 @@ class PositivePoint extends Point
    <simpara>
     The example above could be rewritten as follows, which would allow for the
     <literal>Point</literal> class to add its own <literal>set</literal> hook
-    in the future without issue.  (In the previous example, a hook added to
-    the parent class would be ignored in the child.)
+    in the future without issues (in the previous example, a hook added to
+    the parent class would be ignored in the child).
    </simpara>
    <example>
     <title>Parent hook access (set)</title>