Set c_str_literals stabilization version back to CURRENT_RUSTC_VERSION

`c_str_literals`'s stabilization has been delayed to 1.77 (rust-lang#119528).

Author: eduardosm

compiler/rustc_feature/src/accepted.rs

@@ -77,7 +77,7 @@ declare_features! (
     /// Allows empty structs and enum variants with braces.
     (accepted, braced_empty_structs, "1.8.0", Some(29720)),
     /// Allows `c"foo"` literals.
-    (accepted, c_str_literals, "1.76.0", Some(105723)),
+    (accepted, c_str_literals, "CURRENT_RUSTC_VERSION", Some(105723)),
     /// Allows `#[cfg_attr(predicate, multiple, attributes, here)]`.
     (accepted, cfg_attr_multi, "1.33.0", Some(54881)),
     /// Allows the use of `#[cfg(doctest)]`, set when rustdoc is collecting doctests.