doc: add obs-name, bump version

Author: Bogdanp

gui-easy-lib/info.rkt

@@ -1,7 +1,7 @@
 #lang info
 
 (define license 'BSD-3-Clause)
-(define version "0.19.1")
+(define version "0.20")
 (define collection "racket")
 (define deps
   '("base"

gui-easy/gui/easy/scribblings/reference.scrbl

@@ -878,6 +878,15 @@ that equality (via @racket[equal?]) is preserved for
   observable may be updated.
 }
 
+@defproc[(obs-name [o obs?]) symbol?]{
+  Returns the name of @racket[o].
+
+  @tech{Observables} implement @racket[prop:object-name], so the name of
+  an observable is also accessible generically via @racket[object-name].
+
+  @history[#:added "0.20"]
+}
+
 @defproc[(obs-rename [o obs?]
                      [name symbol?]) obs?]{