Improve documentation example for jsonpath like_regex operator

Make sample like_regex match string values of the root object instead of the
whole document.  The corrected example seems to represent a more relevant
use case.

Backpatch to 12, when jsonpath was introduced.

Discussion: https://postgr.es/m/13440f8b-4c1f-5875-c8e3-f3f65606af2f%40xs4all.nl
Author: Erik Rijkers
Reviewed-by: Michael Paquier, Alexander Korotkov
Backpatch-through: 12

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 930eef9f36e3940fe372ddb98fbfa4e7defcebea..5e8a9fc51375067d2b6a0996f9c031e5cf134c19 100644 (file)
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -16941,9 +16941,10 @@ $[*] ? (@ like_regex "^[aeiou]" flag "i")
      is a JSON path string literal, written according to the rules given in
      <xref linkend="datatype-jsonpath"/>.  This means in particular that any
      backslashes you want to use in the regular expression must be doubled.
-     For example, to match strings that contain only digits:
+     For example, to match string values of the root document that contain
+     only digits:
 <programlisting>
-$ ? (@ like_regex "^\\d+$")
+$.* ? (@ like_regex "^\\d+$")
 </programlisting>
     </para>
    </sect3>