Auto merge of #11918 - ehuss:sync-target-json, r=epage

Sync external-tools JSON docs.

A few fields were missing from the external-tools JSON documentation.

src/doc/src/reference/external-tools.md

@@ -105,10 +105,15 @@ structure:
  This property is not included if no required features are set.
  */
  "required-features": ["feat1"],
+ /* Whether the target should be documented by `cargo doc`. */
+ "doc": true,
  /* Whether or not this target has doc tests enabled, and
  the target is compatible with doc testing.
  */
  "doctest": true
+ /* Whether or not this target should be built and run with `--test`
+ */
+ "test": true
  },
  /* The message emitted by the compiler.
 
@@ -146,6 +151,7 @@ following structure:
  "name": "my-package",
  "src_path": "/path/to/my-package/src/lib.rs",
  "edition": "2018",
+ "doc": true,
  "doctest": true,
  "test": true
  },