Auto merge of #14335 - upsuper:stylo-unit-rerun-build, r=bholley

Add rerun-if-changed for bindings file

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check_bindings.py uses bindings.rs as input, so it should be rerun if that file gets changed.

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

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- [ ] There are tests for these changes OR
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check_bindings.py uses bindings.rs as input, so it should be rerun if
that file gets changed.

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tests/unit/stylo/build.rs

@@ -8,6 +8,7 @@ fn main() {
     println!("cargo:rerun-if-changed=build.rs");
     println!("cargo:rerun-if-changed=check_bindings.py");
     println!("cargo:rerun-if-changed=../../../ports/geckolib/glue.rs");
+    println!("cargo:rerun-if-changed=../../../components/style/gecko_bindings/bindings.rs");
     assert!(Command::new("python").arg("./check_bindings.py")
                                   .spawn().unwrap().wait().unwrap().success());
 }