Replace libstd, libcore, liballoc in line comments.

library/std/src/sys/unix/mod.rs

@@ -164,7 +164,7 @@ pub unsafe fn init(argc: isize, argv: *const *const u8, sigpipe: u8) {
     unsafe fn reset_sigpipe(#[allow(unused_variables)] sigpipe: u8) {
         #[cfg(not(any(target_os = "emscripten", target_os = "fuchsia", target_os = "horizon")))]
         {
-            // We don't want to add this as a public type to libstd, nor do we
+            // We don't want to add this as a public type to std, nor do we
             // want to `include!` a file from the compiler (which would break
             // Miri and xargo for example), so we choose to duplicate these
             // constants from `compiler/rustc_session/src/config/sigpipe.rs`.

library/std/src/sys/unix/net.rs

@@ -512,7 +512,7 @@ impl FromRawFd for Socket {
 // A workaround for this bug is to call the res_init libc function, to clear
 // the cached configs. Unfortunately, while we believe glibc's implementation
 // of res_init is thread-safe, we know that other implementations are not
-// (https://github.com/rust-lang/rust/issues/43592). Code here in libstd could
+// (https://github.com/rust-lang/rust/issues/43592). Code here in std could
 // try to synchronize its res_init calls with a Mutex, but that wouldn't
 // protect programs that call into libc in other ways. So instead of calling
 // res_init unconditionally, we call it only when we detect we're linking