updated Doc string in Base.Generator (#35261)

base/generator.jl

@@ -5,25 +5,26 @@
 
 Given a function `f` and an iterator `iter`, construct an iterator that yields
 the values of `f` applied to the elements of `iter`.
-The syntax for constructing an instance of this type is `f(x) for x in iter [if cond(x)::Bool] `.
-The `[if cond(x)::Bool]` expression is optional and acts as a "guard", effectively
-filtering out values where the condition is false.
+The syntax `f(x) for x in iter` is syntax for constructing an instance of this
+type.
 
 ```jldoctest
-julia> g = (abs2(x) for x in 1:5 if x != 3);
+julia> g = (abs2(x) for x in 1:5);
 
 julia> for x in g
  println(x)
  end
 1
 4
+9
 16
 25
 
 julia> collect(g)
-4-element Vector{Int64}:
+5-element Vector{Int64}:
  1
  4
+ 9
  16
  25
 ```