diff --git a/doc/src/sgml/pgtrgm.sgml b/doc/src/sgml/pgtrgm.sgml
index dde02634ae..97b3d13a88 100644
--- a/doc/src/sgml/pgtrgm.sgml
+++ b/doc/src/sgml/pgtrgm.sgml
@@ -391,13 +391,13 @@ CREATE INDEX trgm_idx ON test_trgm USING GIN (t gin_trgm_ops);
  </para>

  <para>
   <literal>gist_trgm_ops</literal> GiST opclass approximates {+a+} set of
   trigrams as a bitmap signature.  [-Optional-]{+Its optional+} integer parameter
   <literal>siglen</literal>[-of <literal>gist_trgm_ops</literal>-] determines {+the+}
   signature length in bytes.  [-Default signature-]{+The default+} length is 12 bytes.
   Valid values of signature length are between 1 and 2024 bytes.  Longer
   signatures [-leads-]{+lead+} to {+a+} more precise search [-(scan less-]{+(scanning a smaller+} fraction of [-index, scan-]