Prelude: rename and consolidate extension traits

This commit renames a number of extension traits for slices and string
slices, now that they have been refactored for DST. In many cases,
multiple extension traits could now be consolidated. Further
consolidation will be possible with generalized where clauses.

The renamings are consistent with the [new `-Prelude`
suffix](https://github.com/rust-lang/rfcs/pull/344). There are probably
a few more candidates for being renamed this way, but that is left for
API stabilization of the relevant modules.

Because this renames traits, it is a:

[breaking-change]

However, I do not expect any code that currently uses the standard
library to actually break.

Closes #17917

1 files changed, 2 insertions, 2 deletions

diff --git a/src/libcore/fmt/float.rs b/src/libcore/fmt/float.rs
index f51d3948757..a6e5b0cff55 100644
--- a/src/libcore/fmt/float.rs
+++ b/src/libcore/fmt/float.rs
@@ -16,8 +16,8 @@ use iter::{range, DoubleEndedIterator};
 use num::{Float, FPNaN, FPInfinite, ToPrimitive, Primitive};
 use num::{Zero, One, cast};
 use result::Ok;
-use slice::{mod, ImmutableSlice, MutableSlice};
-use str::StrSlice;
+use slice::{mod, SlicePrelude};
+use str::StrPrelude;
 
 /// A flag that specifies whether to use exponential (scientific) notation.
 pub enum ExponentFormat {