[llvm] [llvm-lit][test] Updated built-in cat command tests (PR #104473)

[Paul Kirth via llvm-commits]

================
@@ -1,3 +1,3 @@
-# Check error on an unsupported option for cat .
+## Test error on an unsupported option for cat .
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ilovepi wrote:

```suggestion
## Test error on an unsupported option for cat.
```

https://github.com/llvm/llvm-project/pull/104473