Remove the common prelude module

This fixes the issues described in
https://github.com/rust-lang/rust/issues/136102. Primarily, this
resolves some issues with how the documentation for the prelude is
generated:

- It avoids showing "unstable" for macros in the prelude that are
  actually stable.
- Avoids duplication of some pages due to the previous lack of
  `doc(no_inline)`.
- Makes the different edition preludes consistent, and sets a pattern
  that can be used by future editions.

We may need to rearrange these modules in the future if we decide to
remove anything from the prelude again. If we do, I think we should look
into a different solution that avoids the documentation problems.

tests/rustdoc-js-std/vec-new.js

@@ -9,7 +9,7 @@ const EXPECTED = [
     {
         'query': 'prelude::vec',
         'others': [
-            { 'path': 'std::prelude::rust_2024', 'name': 'Vec' },
+            { 'path': 'std::prelude::v1', 'name': 'Vec' },
         ],
     },
     {