[clang] [clang][Diagnostics] Make 'note' color CYAN (PR #66997)

[Timm Baeder via cfe-commits]

https://github.com/tbaederr created https://github.com/llvm/llvm-project/pull/66997

Just using BLACK makes it invisible in terminals with a dark background.

See this screenshot:

![Screenshot from 2023-09-21 12-03-15](https://github.com/llvm/llvm-project/assets/49720664/245a9c4f-da27-4dbd-a14e-15a01adbc734)

With current clang, the "note:" part of the note is almost invisible, because we select BLACK as its color.

Use CYAN instead, which is also what gcc does.

>From b5445f2b4f4ba8a274cab1c33632f8e74cea0873 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timm=20B=C3=A4der?= <tbaeder at redhat.com>
Date: Thu, 21 Sep 2023 12:01:30 +0200
Subject: [PATCH] [clang][Diagnostics] Make 'note' color CYAN

Just using BLACK makes it invisible in terminals with a dark background.
---
 clang/lib/Frontend/TextDiagnostic.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/clang/lib/Frontend/TextDiagnostic.cpp b/clang/lib/Frontend/TextDiagnostic.cpp
index eaa6e8d29a1dece..89c7ef505159e13 100644
--- a/clang/lib/Frontend/TextDiagnostic.cpp
+++ b/clang/lib/Frontend/TextDiagnostic.cpp
@@ -25,7 +25,7 @@
 using namespace clang;
 
 static const enum raw_ostream::Colors noteColor =
-  raw_ostream::BLACK;
+  raw_ostream::CYAN;
 static const enum raw_ostream::Colors remarkColor =
   raw_ostream::BLUE;
 static const enum raw_ostream::Colors fixitColor =