[clang] [analyzer][NFC] Add some docs for LazyCompoundValue (PR #97407)

[Artem Dergachev via cfe-commits]

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@@ -326,6 +326,12 @@ class LocAsInteger : public NonLoc {
   static bool classof(SVal V) { return V.getKind() == LocAsIntegerKind; }
 };
 
+/// The simplest example of a concrete compound value is nonloc::CompoundVal,
+/// which represents a concrete r-value of an initializer-list or a string.
+/// Internally, it contains an llvm::ImmutableList of SVal's stored inside the
+/// literal.
+///
+/// Source: https://github.com/haoNoQ/clang-analyzer-guide, v0.1, section 5.3.2.
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haoNoQ wrote:

Yeah please nuke this thank you ^.^

Sometimes we cite the academic papers that describe the specific approaches we've implemented (IPA is a good example) but this one's definitely inside out. The source code should be the primary source of truth about the source code.

https://github.com/llvm/llvm-project/pull/97407