Fix generation of distribution tarball

This issue can be reproduced by running `make dist` from the root of the
tree.  Error introduced in fcb21b3, where additions of links in
installation.sgml require custom rules in standalone-profile.xsl to make
sure that ./INSTALL is generated correctly for the distribution tarball,
where links are replaced by equivalent terms from the profile file
changed by this commit.

Per buildfarm member guaibasaurus.

Discussion: https://postgr.es/m/ZD859FmcMRCNtz0W@paquier.xyz

doc/src/sgml/standalone-profile.xsl

@@ -40,6 +40,10 @@ variant without links and references to the main documentation.
   <xsl:text>the documentation about client authentication and libpq</xsl:text>
 </xsl:template>
 
+<xsl:template match="xref[@linkend='collation']">
+  <xsl:text>the documentation</xsl:text>
+</xsl:template>
+
 <xsl:template match="xref[@linkend='docguide-toolsets']">
   <xsl:text>the main documentation's appendix on documentation</xsl:text>
 </xsl:template>
@@ -60,6 +64,10 @@ variant without links and references to the main documentation.
   <xsl:text>the documentation</xsl:text>
 </xsl:template>
 
+<xsl:template match="xref[@linkend='locale-providers']">
+  <xsl:text>the documentation</xsl:text>
+</xsl:template>
+
 <xsl:template match="xref[@linkend='plpython-python23']">
   <xsl:text>the </xsl:text><application>PL/Python</application><xsl:text> documentation</xsl:text>
 </xsl:template>