Add greying out of unactive C/C++ pre-processor block

[Ybalrid]

This is a feature request about the C/C++ developement workflow

Visual Studio proper grey out non active preprocessor block (that doesn't meet the #if or #ifdef conditions)

Here a screenshot of Visual Studio 2017 on a Windows box. The macro _WIN32 is defined here:

Visual Studio Code doesn't handle this functionality at all, here's the same code as shown by VSCode, on a Linux box (_WIN32 not defined. __linux__ defined) :

(the syntax highlighting is also broken, this bug was reported by issue #25198)

[mjbvz]

Related to #15710

[mjbvz]

Tracked on the c++tools extension by microsoft/vscode-cpptools#510

Closing as external