doc: add example of % substitution for connection URIs

bmomjian · bmomjian · commit d61f5bb7c444 · 2017-09-19T12:23:18.000-04:00
Reported-by: Zhou Digoal Discussion: https://postgr.es/m/20170912133722.25637.91@wrigleys.postgresql.org Backpatch-through: 10
diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
@@ -840,7 +840,9 @@ postgresql:///mydb?host=localhost&amp;port=5433
 
    <para>
     Percent-encoding may be used to include symbols with special meaning in any
-    of the <acronym>URI</acronym> parts.
+    of the <acronym>URI</acronym> parts, e.g. replace <literal>=</> with
+    <literal>%3D</>.
+
    </para>
 
    <para>
