Doc: fix up PDF build warnings from over-width table columns.

Addition of multirange info to tables 8.27 and 65.1 made them start
throwing "exceed the available area" warnings in PDF docs builds.

For 8.27, twiddling the existing column width hints was enough to
fix this.  For 65.1, I twiddled the widths a little, but to really
fix it I had to insert a space after each comma in the table, to
allow a line break to occur there.  (This seemed easier to read
and maintain than the alternative of inserting &zwsp; entities.)

Per buildfarm.

doc/src/sgml/datatype.sgml

@@ -4995,8 +4995,8 @@ SELECT * FROM pg_attribute
     <table id="datatype-pseudotypes-table">
      <title>Pseudo-Types</title>
      <tgroup cols="2">
-      <colspec colname="col1" colwidth="1*"/>
-      <colspec colname="col2" colwidth="2*"/>
+      <colspec colname="col1" colwidth="2*"/>
+      <colspec colname="col2" colwidth="3*"/>
       <thead>
        <row>
         <entry>Name</entry>

doc/src/sgml/gist.sgml

@@ -54,6 +54,9 @@
   <table id="gist-builtin-opclasses-table">
    <title>Built-in <acronym>GiST</acronym> Operator Classes</title>
    <tgroup cols="3">
+     <colspec colname="col1" colwidth="2*"/>
+     <colspec colname="col2" colwidth="3*"/>
+     <colspec colname="col3" colwidth="2*"/>
     <thead>
      <row>
       <entry>Name</entry>