Non-char string literals lead to assertion failures

[zeule]

In particular, many tests fail at this assertion:

 /usr/lib/llvm/12/include/clang/AST/Expr.h:1839: llvm::StringRef clang::StringLiteral::getString() const: Assertion `getCharByteWidth() == 1 && "This function is used in places that assume strings use char"' failed.`

[zeule]

a workaround:

diff --git a/sources/libClangSharp/ClangSharp.cpp b/sources/libClangSharp/ClangSharp.cpp
index 9c8ef35..fbc3d32 100644
--- a/sources/libClangSharp/ClangSharp.cpp
+++ b/sources/libClangSharp/ClangSharp.cpp
@@ -3898,7 +3898,7 @@ CXString clangsharp_Cursor_getStringLiteralValue(CXCursor C) {
         const Stmt* S = getCursorStmt(C);
 
         if (const StringLiteral* SL = dyn_cast<StringLiteral>(S)) {
-            return createDup(SL->getString());
+            return createDup(SL->getBytes());
         }
     }