docs: Minor typo fix: test.sh -> test.py

R=dcheng

Review URL: https://codereview.chromium.org/1688243002

Cr-Commit-Position: refs/heads/master@{#374980}
diff --git a/docs/clang.md b/docs/clang.md
index 516d6fb..5b5b43f 100644
--- a/docs/clang.md
+++ b/docs/clang.md
@@ -59,7 +59,7 @@
 To test the FindBadConstructs plugin, run:
 
     (cd tools/clang/plugins/tests && \
-     ./test.sh ../../../../third_party/llvm-build/Release+Asserts/bin/clang \
+     ./test.py ../../../../third_party/llvm-build/Release+Asserts/bin/clang \
                ../../../../third_party/llvm-build/Release+Asserts/lib/libFindBadConstructs.so)
 
 To run [other plugins](writing_clang_plugins.md), add these to your