doc: Add a note that refint will be removed in v20

refint has been removed from the spi contrib module in v20.  Add a note
to the documentation of the still-supported back branches so that users
are aware the module is going away.

Author: Ayush Tiwari <ayushtiwari.slg01@gmail.com>
Reported-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/CAJTYsWUHq8Ohc6-N-xamOPYz-q3qUYMtwQX-1=Zi=5N1Q_GSEQ@mail.gmail.com
Backpatch-through: 14

diff --git a/doc/src/sgml/contrib-spi.sgml b/doc/src/sgml/contrib-spi.sgml
index 7e4e580bc74537f8f073778213ee6033807921f6..9f397aeaddfd47e0a3acce24640b913fd1c5f883 100644 (file)
--- a/doc/src/sgml/contrib-spi.sgml
+++ b/doc/src/sgml/contrib-spi.sgml
@@ -31,7 +31,8 @@
    <function>check_primary_key()</function> and
    <function>check_foreign_key()</function> are used to check foreign key constraints.
    (This functionality is long since superseded by the built-in foreign
-   key mechanism, of course, but the module is still useful as an example.)
+   key mechanism, of course, but the module is still useful as an example.
+   This module will be removed in <productname>PostgreSQL</productname> 20.)
   </para>
 
   <note>