Doc: re-re-revise markup for tables of functions.

Make the markup a bit less ad-hoc.  A function-table cell now contains
several <para> units, and we label the ones that contain function
signatures with role="func_signature".  The CSS or FO stylesheets then
key off of that to decide how to set the indentation.  A very useful
win from this approach is that we can have more than one signature
entry per table cell, simplifying the documentation of closely-related
operators and functions.

This patch mostly just replaces the markup in the tables I converted so
far.  But I did alter a couple of places where multiple signatures were
helpful.

Discussion: https://postgr.es/m/5561.1587922854@sss.pgh.pa.us

doc/src/sgml/stylesheet-common.xsl

@@ -101,11 +101,4 @@
   <xsl:apply-templates select="." mode="xref"/>
 </xsl:template>
 
-
-<!-- Support for explicit line breaks <?br?> within table cells -->
-
-<xsl:template match="processing-instruction('br')">
-  <br/>
-</xsl:template>
-
 </xsl:stylesheet>

doc/src/sgml/stylesheet-fo.xsl

@@ -63,30 +63,14 @@
   </fo:inline>
 </xsl:template>
 
-<!-- overrides built-in DocBook template -->
-<xsl:template name="table.cell.block.properties">
-  <!-- highlight this entry? -->
-  <xsl:choose>
-    <xsl:when test="ancestor::thead or ancestor::tfoot">
-      <xsl:attribute name="font-weight">bold</xsl:attribute>
-    </xsl:when>
-    <!-- Make row headers bold too -->
-    <xsl:when test="ancestor::tbody and
-                    (ancestor::table[@rowheader = 'firstcol'] or
-                    ancestor::informaltable[@rowheader = 'firstcol']) and
-                    ancestor-or-self::entry[1][count(preceding-sibling::entry) = 0]">
-      <xsl:attribute name="font-weight">bold</xsl:attribute>
-    </xsl:when>
-  </xsl:choose>
-  <!-- Postgres additions start here -->
-  <!-- indent all but first line of entries in tables of functions -->
-  <xsl:choose>
-    <xsl:when test="self::entry[@role='functableentry']">
-      <xsl:attribute name="margin-left">4em</xsl:attribute>
+<!-- formatting for entries in tables of functions -->
+<xsl:template match="entry[@role='func_table_entry']/para">
+  <fo:block margin-left="4em" text-align="left">
+    <xsl:if test="self::para[@role='func_signature']">
       <xsl:attribute name="text-indent">-3.5em</xsl:attribute>
-      <xsl:attribute name="text-align">left</xsl:attribute>
-    </xsl:when>
-  </xsl:choose>
+    </xsl:if>
+    <xsl:apply-templates/>
+  </fo:block>
 </xsl:template>
 
 <!-- overrides stylesheet-common.xsl -->
@@ -96,11 +80,6 @@
   <xsl:call-template name="inline.monoseq"/>
 </xsl:template>
 
-<!-- overrides stylesheet-common.xsl -->
-<xsl:template match="processing-instruction('br')">
-  <fo:block/>
-</xsl:template>
-
 <!-- FOP needs us to be explicit about use of symbol font in some cases -->
 <xsl:template match="phrase[@role='symbol_font']">
   <fo:inline font-family="{$symbol.font.family}"><xsl:value-of select="."/></fo:inline>

doc/src/sgml/stylesheet.css

@@ -78,13 +78,24 @@ div.example {
 
 /* formatting for entries in tables of functions: indent all but first line */
 
-th.functableentry,
-td.functableentry {
+th.func_table_entry p,
+td.func_table_entry p {
+	margin-top: 0.1em;
+	margin-bottom: 0.1em;
 	padding-left: 4em;
-	text-indent: -3.5em;
 	text-align: left;
 }
 
+p.func_signature {
+	text-indent: -3.5em;
+}
+
+td.func_table_entry pre.programlisting {
+	margin-top: 0.1em;
+	margin-bottom: 0.1em;
+	padding-left: 4em;
+}
+
 /* Put these here instead of inside the HTML (see unsetting of
    admon.style in XSL) so that the web site stylesheet can set its own
    style. */