Rollup merge of #97904 - est31:master, r=Dylan-DPC

Small grammar fix in the compile_error documentation

Author: matthiaskrgr

library/core/src/macros/mod.rs

@@ -795,7 +795,7 @@ pub(crate) mod builtin {
     ///
     /// Two such examples are macros and `#[cfg]` environments.
     ///
-    /// Emit better compiler error if a macro is passed invalid values. Without the final branch,
+    /// Emit a better compiler error if a macro is passed invalid values. Without the final branch,
     /// the compiler would still emit an error, but the error's message would not mention the two
     /// valid values.
     ///
@@ -812,7 +812,7 @@ pub(crate) mod builtin {
     /// // ^ will fail at compile time with message "This macro only accepts `foo` or `bar`"
     /// ```
     ///
-    /// Emit compiler error if one of a number of features isn't available.
+    /// Emit a compiler error if one of a number of features isn't available.
     ///
     /// ```compile_fail
     /// #[cfg(not(any(feature = "foo", feature = "bar")))]