fix!: allow &str to be parsed as key properly

Previously there were lifetime issue because the key
needed the same lifetime as the underlying parsed file,
which was hard to accomplish even with `&'static str'`
as it really needed "&'static &'static str".

However, this also means that owned keys can't be passed
anymore.

Author: Byron

gix-config/src/key.rs

@@ -1,7 +1,7 @@
 use bstr::{BStr, ByteSlice};
 
 /// Parse parts of a Git configuration key, like `remote.origin.url` or `core.bare`.
-pub trait AsKey {
+pub trait AsKey: Copy {
     /// Return a parsed key reference, containing all relevant parts of a key.
     /// For instance, `remote.origin.url` such key would yield access to `("remote", Some("origin"), "url")`
     /// while `user.name` would yield `("user", None, "name")`.
@@ -22,7 +22,7 @@ mod impls {
 
     use crate::key::{AsKey, KeyRef};
 
-    impl AsKey for String {
+    impl AsKey for &String {
         fn as_key(&self) -> KeyRef<'_> {
             self.try_as_key()
                 .unwrap_or_else(|| panic!("'{self}' is not a valid configuration key"))
@@ -44,7 +44,7 @@ mod impls {
         }
     }
 
-    impl AsKey for BString {
+    impl AsKey for &BString {
         fn as_key(&self) -> KeyRef<'_> {
             self.try_as_key()
                 .unwrap_or_else(|| panic!("'{self}' is not a valid configuration key"))