Fix conflicting id tags (sql.sgml also used "select-title").

doc/src/sgml/ref/select.sgml

 <refentry id="SQL-SELECT">
  <refmeta>
-  <refentrytitle id="select-title">
+  <refentrytitle id="sql-select-title">
    SELECT
   </refentrytitle>
   <refmiscinfo>SQL - Language Statements</refmiscinfo>

doc/src/sgml/ref/select_into.sgml

@@ -38,7 +38,7 @@ SELECT [ ALL | DISTINCT ] <replaceable class="PARAMETER">expression</replaceable
    </title>
    <para>
     All input fields are described in detail for
-    <xref linkend="select-title" endterm="select-title">.
+    <xref linkend="sql-select-title" endterm="sql-select-title">.
    </para>
   </refsect2>
 
@@ -51,7 +51,7 @@ SELECT [ ALL | DISTINCT ] <replaceable class="PARAMETER">expression</replaceable
    </title>
    <para>
     All output fields are described in detail for
-    <xref linkend="select-title" endterm="select-title">.
+    <xref linkend="sql-select-title" endterm="sql-select-title">.
    </para>
   </refsect2>
  </refsynopsisdiv>