Rollup merge of rust-lang#136279 - Zalathar:ensure-ok, r=oli-obk

Rename `tcx.ensure()` to `tcx.ensure_ok()`, and improve the associated docs

This is all based on my archaeology for https://rust-lang.zulipchat.com/#narrow/channel/182449-t-compiler.2Fhelp/topic/.60TyCtxtEnsure.60.

The main renamings are:
- `tcx.ensure()` → `tcx.ensure_ok()`
- `tcx.ensure_with_value()` → `tcx.ensure_done()`
- Query modifier `ensure_forwards_result_if_red` → `return_result_from_ensure_ok`

Hopefully these new names are a better fit for the *actual* function and purpose of these query call modes.

Author: matthiaskrgr

clippy_lints/src/ctfe.rs

@@ -21,6 +21,6 @@ impl<'tcx> LateLintPass<'tcx> for ClippyCtfe {
         _: Span,
         defid: LocalDefId,
     ) {
-        cx.tcx.ensure().mir_drops_elaborated_and_const_checked(defid); // Lint
+        cx.tcx.ensure_ok().mir_drops_elaborated_and_const_checked(defid); // Lint
     }
 }