JuliaLang#55055: Remove incorrect BoundsError mention from iterate(st…

…ring) docs.

Since at least v1.6 a bounds error has not been thrown if you iterate
outside the bounds of the string.

base/strings/basic.jl

@@ -146,9 +146,8 @@ Stacktrace:
 
 Return a tuple of the character in `s` at index `i` with the index of the start
 of the following character in `s`. This is the key method that allows strings to
-be iterated, yielding a sequences of characters. If `i` is out of bounds in `s`
-then a bounds error is raised. The `iterate` function, as part of the iteration
-protocol may assume that `i` is the start of a character in `s`.
+be iterated, yielding a sequences of characters. The `iterate` function, as part
+of the iteration protocol may assume that `i` is the start of a character in `s`.
 
 See also [`getindex`](@ref), [`checkbounds`](@ref).
 """