types: add String::to_str()

crates/types/src/string.rs

@@ -2,6 +2,7 @@
 
 use alloc::borrow::Cow;
 use alloc::string::String as StdString;
+use core::str::{self, Utf8Error};
 use core::{ffi, slice};
 use std::path::{Path, PathBuf};
 
@@ -106,6 +107,12 @@ impl String {
         NonOwning::new(Self { ..*self })
     }
 
+    /// Yields a string slice if the [`String`]'s contents are valid UTF-8.
+    #[inline]
+    pub fn to_str(&self) -> Result<&str, Utf8Error> {
+        str::from_utf8(self.as_bytes())
+    }
+
     /// Converts the `String` into Rust's `std::string::String`. If it already
     /// holds a valid UTF-8 byte sequence no allocation is made. If it doesn't
     /// the `String` is copied and all invalid sequences are replaced with `�`.