Add #[inline] to the Utf8Error accessors.

Author: m-ou-se

library/core/src/str/error.rs

@@ -72,6 +72,7 @@ impl Utf8Error {
     /// assert_eq!(1, error.valid_up_to());
     /// ```
     #[stable(feature = "utf8_error", since = "1.5.0")]
+    #[inline]
     pub fn valid_up_to(&self) -> usize {
         self.valid_up_to
     }
@@ -92,6 +93,7 @@ impl Utf8Error {
     ///
     /// [U+FFFD]: ../../std/char/constant.REPLACEMENT_CHARACTER.html
     #[stable(feature = "utf8_error_error_len", since = "1.20.0")]
+    #[inline]
     pub fn error_len(&self) -> Option<usize> {
         self.error_len.map(|len| len as usize)
     }