docs: remove outdated note about unique indexes

Patch by Josh Kupershmidt

Backpatch through 9.5

diff --git a/doc/src/sgml/indices.sgml b/doc/src/sgml/indices.sgml
index 309fd1269bd6056e3d0675fba8e4ac05a7aeae73..2d131c9109779223af849ed6d3bbc44aad66d614 100644 (file)
--- a/doc/src/sgml/indices.sgml
+++ b/doc/src/sgml/indices.sgml
@@ -655,11 +655,7 @@ CREATE UNIQUE INDEX name ON table
 
   
    
-    The preferred way to add a unique constraint to a table is
-    ALTER TABLE ... ADD CONSTRAINT.  The use of
-    indexes to enforce unique constraints could be considered an
-    implementation detail that should not be accessed directly.
-    One should, however, be aware that there's no need to manually
+    There's no need to manually
     create indexes on unique columns; doing so would just duplicate
     the automatically-created index.