Drop outdated sentence in given instance doc

Author: odersky

docs/docs/reference/contextual/delegates.md

@@ -68,8 +68,7 @@ An alias given can have type parameters and given clauses just like any other gi
 ## Given Instance Initialization
 
 A given instance without type parameters or given clause is initialized on-demand, the first
-time it is accessed. It is not required to ensure safe publication, which means that
-different threads might create different instances for the same `given` definition.
+time it is accessed.
 If a `given` definition has type parameters or a given clause, a fresh instance is created for each reference.
 
 ## Syntax