[llvm] [MC][RISCV] Add assembly syntax highlighting for RISCV (PR #65853)

[Jonas Devlieghere via llvm-commits]

================
@@ -256,6 +278,8 @@ void RISCVInstPrinter::printSpimm(const MCInst *MI, unsigned OpNo,
   if (Opcode == RISCV::CM_PUSH)
     Spimm = -Spimm;
 
+  // RAII guard for ANSI color escape sequences
----------------
JDevlieghere wrote:

Someone else pointed out that this was a little confusing. For the ARM backend (#65561) I did the following to make it more obvious: 

```
WithMarkup ScopedMarkup = markup(O, Markup::Immediate);
...
```



https://github.com/llvm/llvm-project/pull/65853