[clang] [HLSL][RootSignature] Implement Lexing of DescriptorTables (PR #122981)

[Finn Plummer via cfe-commits]

================
@@ -0,0 +1,153 @@
+#include "clang/Parse/ParseHLSLRootSignature.h"
+
+namespace llvm {
+namespace hlsl {
+namespace root_signature {
+
+// Lexer Definitions
+
+static bool IsNumberChar(char C) {
+  // TODO: extend for float support with or without hexadecimal/exponent
----------------
inbelic wrote:

Yep, I agree. In this case, it will be added when I get to supporting `StaticSampler`s so it will be gone by the time the parent issue is resolved. I could update the todo to reference the parent issue though?

https://github.com/llvm/llvm-project/pull/122981