Optimization of tilde expansion (#9709)

* Use next and avoid a redundant prefix strip

* Avoid allocations

Especially when `expand_tilde` is claled on a path
that doesn't contain a tilde.

* Add a test

* Use Into<Cow<…>>

* Put the expand_tilde test at the end of the file

* Remove unused importsw

1 files changed, 2 insertions, 2 deletions

diff --git a/helix-term/src/ui/mod.rs b/helix-term/src/ui/mod.rs
index d27e8355..0873116c 100644
--- a/helix-term/src/ui/mod.rs
+++ b/helix-term/src/ui/mod.rs
@@ -428,9 +428,9 @@ pub mod completers {
                 path
             } else {
                 match path.parent() {
-                    Some(path) if !path.as_os_str().is_empty() => path.to_path_buf(),
+                    Some(path) if !path.as_os_str().is_empty() => Cow::Borrowed(path),
                     // Path::new("h")'s parent is Some("")...
-                    _ => helix_stdx::env::current_working_dir(),
+                    _ => Cow::Owned(helix_stdx::env::current_working_dir()),
                 }
             };