Fix broken markup.

doc/src/sgml/sources.sgml

-<!-- $PostgreSQL: pgsql/doc/src/sgml/sources.sgml,v 2.26 2007/02/01 21:28:34 momjian Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/sources.sgml,v 2.27 2007/02/01 22:06:14 tgl Exp $ -->
 
  <chapter id="source">
   <title>PostgreSQL Coding Conventions</title>
@@ -606,17 +606,13 @@ BETTER: unrecognized node type: 42
   </formalpara>
 
   <formalpara>
-    <title>May/Can/Might</title>
+    <title>May vs. Can vs. Might</title>
    <para>
-    <quote>May</quote> suggests permission (e.g. "You may borrow my rake.")
+    <quote>May</quote> suggests permission (e.g. "You may borrow my rake."),
     and has little use in documentation or error messages.
     <quote>Can</quote> suggests ability (e.g. "I can lift that log."),
     and <quote>might</quote> suggests possibility (e.g. "It might rain
-    today.").
-   </para>
-
-   <para>
-    Rationale: Using the proper word clarifies meaning and assists
+    today.").  Using the proper word clarifies meaning and assists
     translation.
    </para>
   </formalpara>