remove unicode.Rune16 without deprecation period; fixes https://github.com/nim-lang/RFCs/issues/151 (#12072)

changelog.md

@@ -19,6 +19,18 @@
 
 ### Breaking changes in the standard library
 
+- We removed `unicode.Rune16` without any deprecation period as the name
+  was wrong (see the [RFC](https://github.com/nim-lang/RFCs/issues/151) for details)
+  and we didn't find any usages of it in the wild. If you still need it, add this
+  piece of code to your project:
+
+```nim
+
+type
+  Rune16* = distinct int16
+
+```
+
 
 ### Breaking changes in the compiler
 

lib/pure/unicode.nim

@@ -31,11 +31,6 @@ type
     ## Type that can hold a single Unicode code point.
     ##
     ## A Rune may be composed with other Runes to a character on the screen.
-  Rune16* = distinct int16 ## \
-    ## Type that can hold a single UTF-16 encoded character.
-    ##
-    ## A single Rune16 may not be enough to hold an arbitrary Unicode code point.
-
 
 template ones(n: untyped): untyped = ((1 shl n)-1)