Rename Iterator::len to count

This commit carries out the request from issue #14678:

> The method `Iterator::len()` is surprising, as all the other uses of
> `len()` do not consume the value. `len()` would make more sense to be
> called `count()`, but that would collide with the current
> `Iterator::count(|T| -> bool) -> unit` method. That method, however, is
> a bit redundant, and can be easily replaced with
> `iter.filter(|x| x < 5).count()`.
> After this change, we could then define the `len()` method
> on `iter::ExactSize`.

Closes #14678.

[breaking-change]

1 files changed, 0 insertions, 1 deletions

diff --git a/src/libstd/num/strconv.rs b/src/libstd/num/strconv.rs
index 54ca5797804..133a8db90fa 100644
--- a/src/libstd/num/strconv.rs
+++ b/src/libstd/num/strconv.rs
@@ -13,7 +13,6 @@
 use char;
 use clone::Clone;
 use container::Container;
-use iter::Iterator;
 use num::{NumCast, Zero, One, cast, Int};
 use num::{Float, FPNaN, FPInfinite, ToPrimitive};
 use num;