[clang] [clang][dataflow] Show triangle in `<details>` element. (PR #67431)

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@@ -122,10 +122,22 @@ code.line:has(.bb-select):before {
   font-size: x-small;
   flex-grow: 1;
 }
-.value summary {
+.value > summary {
   background-color: #ace;
   display: flex;
   justify-content: space-between;
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martinboehme wrote:

Ah, true! Changed to `start`, which appears to solve this:

![image](https://github.com/llvm/llvm-project/assets/29098113/f9349b1d-767e-48ed-ae61-77eefb67b210)


https://github.com/llvm/llvm-project/pull/67431