Merge branch 'robbert/remove_old_set_notations' into 'master'

Remove singleton notations for tuples

See merge request iris/stdpp!233

CHANGELOG.md

 This file lists "large-ish" changes to the std++ Coq library, but not every
 API-breaking change is listed.
 
+## std++ master
+
+- Remove singleton notations `{[ x,y ]}` and `{[ x,y,z ]}` for `{[ (x,y) ]}`
+  and `{[ (x,y,z) ]}`. They date back to the time we used the `singleton` class
+  with a product for maps (there's now the `singletonM` class).
+
 ## std++ 1.5.0
 
 Coq 8.13 is newly supported by this release, Coq 8.8 and 8.9 are no longer

theories/base.v

@@ -865,10 +865,6 @@ Notation "{[ x ]}" := (singleton x) (at level 1) : stdpp_scope.
 Notation "{[ x ; y ; .. ; z ]}" :=
   (union .. (union (singleton x) (singleton y)) .. (singleton z))
   (at level 1) : stdpp_scope.
-Notation "{[ x , y ]}" := (singleton (x,y))
-  (at level 1, y at next level) : stdpp_scope.
-Notation "{[ x , y , z ]}" := (singleton (x,y,z))
-  (at level 1, y at next level, z at next level) : stdpp_scope.
 
 Class SubsetEq A := subseteq: relation A.
 Global Hint Mode SubsetEq ! : typeclass_instances.