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

Diff for: src/driver/aot.rs

@@ -692,7 +692,7 @@ pub(crate) fn run_aot(
 
     if tcx.dep_graph.is_fully_enabled() {
         for cgu in cgus {
-            tcx.ensure().codegen_unit(cgu.name());
+            tcx.ensure_ok().codegen_unit(cgu.name());
         }
     }