Add names.preludes.extern.no_std.syntax

Author: ehuss

src/names/preludes.md

@@ -82,6 +82,9 @@ r[names.preludes.extern.no_std]
 r[names.preludes.extern.no_std.intro]
 By default, the standard library is automatically included in the crate root module. The [`std`] crate is added to the root, along with an implicit [`macro_use` attribute] pulling in all macros exported from `std` into the [`macro_use` prelude]. Both [`core`] and [`std`] are added to the [extern prelude].
 
+r[names.preludes.extern.no_std.syntax]
+The `no_std` attribute uses the [MetaWord] syntax and thus does not take any inputs.
+
 r[names.preludes.extern.no_std.allowed-positions]
 The *`no_std` [attribute]* may be applied at the crate level to prevent the [`std`] crate from being automatically added into scope.