xrefs: Generate Rust compile commands for Kythe

Run `//:update_host_kernel_compile_commands` in xrefs recipe to generate
rust-project.json for Kythe Rust indexing.

Test: ./recipes.py test
Change-Id: I2a740a1bfbd8082e7574b428517a2185eff5a185
Reviewed-on: https://pigweed-review.googlesource.com/c/infra/recipes/+/476645

recipes/xrefs.py

diff --git a/recipes/xrefs.py b/recipes/xrefs.py
index 5864d02..87f3160 100644
--- a/recipes/xrefs.py
+++ b/recipes/xrefs.py
@@ -75,6 +75,12 @@
             ['bazel', 'run', '//:update_host_compile_commands'],
         )
 
+        # Generate Rust compile commands using Bazel
+        api.step(
+            'Generate Rust compile commands',
+            ['bazel', 'run', '//:update_host_kernel_compile_commands'],
+        )
+
         # Extract Kythe compilation units and upload to GCS
         kzip_path = checkout.root / f'{checkout.revision()}.kzip'
         extract_args = [
@@ -120,6 +126,10 @@
         ),
         api.post_process(
             post_process.MustRun,
+            'Generate Rust compile commands',
+        ),
+        api.post_process(
+            post_process.MustRun,
             'Extract Kythe kzip',
         ),
         api.post_process(
@@ -138,6 +148,10 @@
         ),
         api.post_process(
             post_process.MustRun,
+            'Generate Rust compile commands',
+        ),
+        api.post_process(
+            post_process.MustRun,
             'Extract Kythe kzip',
         ),
         drop_expectations_must_be_last(),
@@ -153,6 +167,10 @@
         ),
         api.post_process(
             post_process.MustRun,
+            'Generate Rust compile commands',
+        ),
+        api.post_process(
+            post_process.MustRun,
             'Extract Kythe kzip',
         ),
         drop_expectations_must_be_last(),