Auto merge of #147282 - Zalathar:rollup-7wz3k9r, r=Zalathar

Rollup of 6 pull requests

Successful merges:

 - rust-lang/rust#141839 (make rust-analyzer use a dedicated build directory)
 - rust-lang/rust#146166 (Implement range support in `//@ edition`)
 - rust-lang/rust#147259 (cg_llvm: Use helper methods for all calls to `LLVMMDNodeInContext2`)
 - rust-lang/rust#147263 (Disable triagebot auto stable-regression compiler backport nominations pending redesign)
 - rust-lang/rust#147268 (add arm-maintainers to various targets)
 - rust-lang/rust#147270 (Move doc_cfg-specific code into `cfg.rs`)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

src/tests/directives.md

@@ -262,6 +262,20 @@ Consider writing the test as a proper incremental test instead.
 
 </div>
 
+#### The edition directive
+
+The `//@ edition` directive can take an exact edition, a bounded half-open range of editions or a left-bounded half-open range of editions, this affects which edition is used by `./x test` to run the test. For example:
+
+- A test with the `//@ edition: 2018` directive will only run under the 2018 edition.
+- A test with the `//@ edition: 2015..2021` directive can be run under both the 2015 and 2018 editions. However, CI will only run the test with the lowest edition possible (2015 in this case).
+- A test with the `//@ edition: 2018..` directive will run under any edition greater or equal than 2018. However, CI will only run the test with the lowest edition possible (2018 in this case).
+
+You can also force `./x test` to use a specific edition by passing the `-- --edition=` argument. However, tests with the `//@ edition` directive will clamp the value passed to the argument. For example, if we run `./x test -- --edition=2015`:
+
+- A test with the `//@ edition: 2018` will run with the 2018 edition. 
+- A test with the `//@ edition: 2015..2021` will be run with the 2015 edition. 
+- A test with the `//@ edition: 2018..` will run with the 2018 edition. 
+
 ### Rustdoc
 
 | Directive   | Explanation                                                  | Supported test suites                   | Possible values           |