Stabilize std::path

This commit stabilizes essentially all of the new `std::path` API. The
API itself is changed in a couple of ways (which brings it in closer
alignment with the RFC):

* `.` components are now normalized away, unless they appear at the
  start of a path. This in turn effects the semantics of e.g. asking for
  the file name of `foo/` or `foo/.`, both of which yield `Some("foo")`
  now. This semantics is what the original RFC specified, and is also
  desirable given early experience rolling out the new API.

* The `parent` function now succeeds if, and only if, the path has at
  least one non-root/prefix component. This change affects `pop` as
  well.

* The `Prefix` component now involves a separate `PrefixComponent`
  struct, to better allow for keeping both parsed and unparsed prefix data.

In addition, the `old_path` module is now deprecated.

Closes #23264

[breaking-change]

2 files changed, 2 insertions, 2 deletions

diff --git a/src/test/auxiliary/cross_crate_spans.rs b/src/test/auxiliary/cross_crate_spans.rs
index 22c206836ee..91a480ac86b 100644
--- a/src/test/auxiliary/cross_crate_spans.rs
+++ b/src/test/auxiliary/cross_crate_spans.rs
@@ -23,4 +23,4 @@ pub fn generic_function<T: Clone>(val: T) -> (T, T) {
 }
 
 #[inline(never)]
-fn zzz() {()}
\ No newline at end of file
+fn zzz() {()}
diff --git a/src/test/compile-fail/custom_attribute.rs b/src/test/compile-fail/custom_attribute.rs
index 193063a98cb..4e089a4e59c 100644
--- a/src/test/compile-fail/custom_attribute.rs
+++ b/src/test/compile-fail/custom_attribute.rs
@@ -11,4 +11,4 @@
 #[foo] //~ ERROR The attribute `foo`
 fn main() {
 
-}
\ No newline at end of file
+}