docs: document official external commands

This documents external commands that are distributed along with
the Rust toolchain, including

* `cargo-clippy`
* `cargo-fmt`
* `cargo-miri`

The purpose of this is increasing the visibility of these tools,
and redirecting people to the correct place to discuss and learn them.

Author: weihanglo

src/doc/src/SUMMARY.md

@@ -92,6 +92,10 @@
         * [cargo package](commands/cargo-package.md)
         * [cargo publish](commands/cargo-publish.md)
         * [cargo yank](commands/cargo-yank.md)
+    * [External Commands](commands/external-commands.md)
+        * [cargo clippy](commands/cargo-clippy.md)
+        * [cargo fmt](commands/cargo-fmt.md)
+        * [cargo miri](commands/cargo-miri.md)
 
 * [FAQ](faq.md)
 * [Appendix: Glossary](appendix/glossary.md)

src/doc/src/commands/cargo-clippy.md

@@ -0,0 +1,20 @@
+# cargo-clippy(1)
+
+## NAME
+
+cargo-miri --- Checks a package to catch common mistakes and improve your Rust code
+
+## DESCRIPTION
+
+This is an external command distributed with the Rust toolchain as an optional component.
+It is not built into Cargo, and may require additional installation.
+
+For information about usage and installation,
+see [Clippy Documentation](../../clippy/).
+
+## SEE ALSO
+
+[cargo(1)](cargo.md),
+[cargo-fix(1)](cargo-fix.md),
+[cargo-fmt(1)](cargo-fmt.md),
+[Custom subcommands](../reference/external-tools.md#custom-subcommands)

src/doc/src/commands/cargo-fmt.md

@@ -0,0 +1,20 @@
+# cargo-fmt(1)
+
+## NAME
+
+carog-fmt --- Formats all bin and lib files of the current crate using rustfmt
+
+## DESCRIPTION
+
+This is an external command distributed with the Rust toolchain as an optional component.
+It is not built into Cargo, and may require additional installation.
+
+For information about usage and installation,
+see <https://github.com/rust-lang/rustfmt>.
+
+## SEE ALSO
+
+[cargo(1)](cargo.md),
+[cargo-fix(1)](cargo-fix.md),
+[cargo-clippy(1)](cargo-clippy.md),
+[Custom subcommands](../reference/external-tools.md#custom-subcommands)

src/doc/src/commands/cargo-miri.md

@@ -0,0 +1,20 @@
+# cargo-miri(1)
+
+## NAME
+
+cargo-miri --- Runs binary crates and tests in Miri
+
+## DESCRIPTION
+
+This is an external command distributed with the Rust toolchain as an optional component.
+It is not built into Cargo, and may require additional installation.
+
+For information about usage and installation,
+see <https://github.com/rust-lang/miri>.
+
+## SEE ALSO
+
+[cargo(1)](cargo.md),
+[cargo-run(1)](cargo-run.md),
+[cargo-test(1)](cargo-test.md),
+[Custom subcommands](../reference/external-tools.md#custom-subcommands)

src/doc/src/commands/external-commands.md

@@ -0,0 +1,11 @@
+# External Commands
+
+This page maintains a list of [external commands] distributed with the Rust
+toolchain as optional components.
+They are not built into Cargo, and may require additional installation.
+
+* [cargo clippy](cargo-clippy.md)
+* [cargo fmt](cargo-fmt.md)
+* [cargo miri](cargo-miri.md)
+
+[external commands]: ../reference/external-tools.md#custom-subcommands

src/doc/src/commands/index.md

@@ -4,3 +4,4 @@
 * [Manifest Commands](manifest-commands.md)
 * [Package Commands](package-commands.md)
 * [Publishing Commands](publishing-commands.md)
+* [External Commands](external-commands.md)