fix: make "Documentation Tests" page up-to-date (#712)

runtime/manual/basics/testing/documentation.md

@@ -3,7 +3,15 @@ title: "Documentation Tests"
 oldUrl: /runtime/manual/testing/documentation/
 ---
 
-Deno supports type-checking your documentation examples.
+Deno supports _type-checking_ your documentation examples.
+
+:::info
+
+No runtime behavior is tested for code snippets in documentation as of now.
+Tracking issue:
+[denoland/deno#4716](https://github.com/denoland/deno/issues/4716)
+
+:::
 
 This makes sure that examples within your documentation are up to date and
 working.
@@ -25,13 +33,32 @@ determined by the language identifier attribute which may be any of the
 following:
 
 - `js`
+- `javascript`
+- `mjs`
+- `cjs`
 - `jsx`
 - `ts`
+- `typescript`
+- `mts`
+- `cts`
 - `tsx`
 
 If no language identifier is specified then the language is inferred from media
 type of the source document that the code block is extracted from.
 
+Another attribute supported is `ignore`, which tells the test runner to skip
+type-checking the code block.
+
+````ts
+/**
+ * # Does not pass type check
+ *
+ * ```typescript ignore
+ * const x: string = 42;
+ * ```
+ */
+````
+
 If this example was in a file named foo.ts, running `deno test --doc foo.ts`
 will extract this example, and then type-check it as a standalone module living
 in the same directory as the module being documented.