Doc: Document known problem with Windows collation versions.

Warn users that locales with traditional Windows NLS names like
"English_United States.1252" won't provide version information, and that
something like initdb --lc-collate=en-US would be needed to fix that
problem for the initial template databases.

Discussion: https://postgr.es/m/CA%2BhUKGJ_hk3rU%3D%3Dg2FpAMChb_4i%2BTJacpjjqFsinY-tRM3FBmA%40mail.gmail.com

diff --git a/doc/src/sgml/charset.sgml b/doc/src/sgml/charset.sgml
index 1b00e543a66ff289e044202b5a79c905c3886017..1c673cc1103a490997a943e8f91e348a09fc78ac 100644 (file)
--- a/doc/src/sgml/charset.sgml
+++ b/doc/src/sgml/charset.sgml
@@ -985,6 +985,15 @@ CREATE COLLATION ignore_accents (provider = icu, locale = 'und-u-ks-level1-kc-tr
      approach is imperfect as maintainers are free to back-port newer
      collation definitions to older C library releases.
     
+    
+     When using Windows collations, version information is only available for
+     collations defined with BCP 47 language tags such as
+     en-US.  Currently, initdb selects
+     a default locale using a traditional Windows language and country
+     string such as English_United States.1252.  The
+     --lc-collate option can be used to provide an explicit
+     locale name in BCP 47 format.
+