Implement From<FixedString> for Box<str> (#12)

Author: Joshix-1

src/string.rs

@@ -1,7 +1,7 @@
 use alloc::{
     borrow::{Cow, ToOwned},
     boxed::Box,
-    string::{String, ToString},
+    string::{String},
     sync::Arc,
 };
 use core::{borrow::Borrow, fmt::Write as _, hash::Hash, str::FromStr};
@@ -315,12 +315,18 @@ impl<LenT: ValidLength> From<char> for FixedString<LenT> {
 }
 
 impl<LenT: ValidLength> From<FixedString<LenT>> for String {
+    fn from(value: FixedString<LenT>) -> Self {
+        Box::<str>::from(value).into()
+    }
+}
+
+impl<LenT: ValidLength> From<FixedString<LenT>> for Box<str> {
     fn from(value: FixedString<LenT>) -> Self {
         match value.0 {
+            FixedStringRepr::Inline(a) => a.as_str().into(),
+            FixedStringRepr::Static(a) => a.as_str().into(),
             // SAFETY: Self holds the type invariant that the array is UTF-8.
-            FixedStringRepr::Heap(a) => unsafe { String::from_utf8_unchecked(a.into()) },
-            FixedStringRepr::Inline(a) => a.as_str().to_string(),
-            FixedStringRepr::Static(a) => a.as_str().to_string(),
+            FixedStringRepr::Heap(a) => unsafe { alloc::str::from_boxed_utf8_unchecked(a.into()) },
         }
     }
 }