Add a cargo_update.py script (#7431)

Our development instructions now recommend installing a number of
binaries through `cargo`. Updating these binaries has to be done by
hand. So we can provide a script that users can use to update them
easily and regularly.

docs/project/contribution_tools.md

@@ -24,6 +24,7 @@ contributions.
     -   [Optional tools](#optional-tools)
         -   [Jujutsu (`jj`)](#jujutsu-jj)
         -   [AI assistants](#ai-assistants)
+    -   [Updating tools installed with `cargo`](#updating-tools-installed-with-cargo)
     -   [Running tests with AddressSanitizer (ASan)](#running-tests-with-addresssanitizer-asan)
     -   [Manually building Clang and LLVM (not recommended)](#manually-building-clang-and-llvm-not-recommended)
 -   [Troubleshooting build issues](#troubleshooting-build-issues)
@@ -251,7 +252,7 @@ considering if they fit your workflow.
         purposes, such as editing files, without interfering with `bazel`.
     -   We also provide recommended setups for debugging in VS Code with either
         [LLDB](/toolchain/docs/debugging.md#debugging-with-lldb) or
-        [GDB]((/toolchain/docs/debugging.md#debugging-with-gdb)
+        [GDB](/toolchain/docs/debugging.md#debugging-with-gdb)
 -   [clangd](https://clangd.llvm.org/installation): An LSP server implementation
     for C/C++.
 
@@ -259,12 +260,10 @@ considering if they fit your workflow.
         generated file called `compile_commands.json`. This can be generated by
         invoking the command below:
 
-        ```
+        ```sh
         ./scripts/create_compdb.py
         ```
 
-        -   **NOTE**: This assumes you have `python` 3 installed on your system.
-
 #### Jujutsu (`jj`)
 
 [Jujutsu](https://github.com/jj-vcs/jj) is a Git-compatible version control
@@ -345,6 +344,16 @@ git show
 git status
 ```
 
+### Updating tools installed with `cargo`
+
+We recommend and use a number of tools that are installed by way of
+`cargo install --locked`. To update these tools you can run the following
+command:
+
+```sh
+./scripts/cargo_update.py
+```
+
 ### Running tests with AddressSanitizer (ASan)
 
 By default, the Bazel build mode for the toolchain does not enable