[clang] [clang-format] Add --fail-on-incomplete-format. (PR #84346)

[Owen Pan via cfe-commits]

================
@@ -0,0 +1,5 @@
+// RUN: cat %s | not clang-format --fail-on-incomplete-format | FileCheck %s
+// RUN: cat %s | clang-format | FileCheck %s
+int a([) {}
+
+// CHECK: int a([) {}
----------------
owenca wrote:

It's missing the EOF. Also, use a single hyphen for the option like other tests.
```suggestion
// RUN: clang-format %s
// RUN: not clang-format %s -fail-on-incomplete-format

int a(
```

https://github.com/llvm/llvm-project/pull/84346