Extension's code formatting ignores CLANG format options file

[Jazzinghen]

Tl;Dr

When formatting HLSL code the resulting format ignores the .clang-format file that's present in the Workspace, if present. I didn't test other languages, but it seems like the extension still doesn't support formatting for shader languages that are not HLSL

Steps to reproduce

• Create a .clang-format file that changes the behaviour of the default C++ formatter options set in VSCode
• Launch formatting on an HLSL file
• The file doesn't follow the non-default options

Potential cause

I tried to look around the code and I think I understood that to format an HLSL file the code creates a temporary copy of the file in the system's temp folder, appends .cpp to it and then calls the standard VSCode format call on it. When using clang-formatter as a formatter provider and with file as a default format style VSCode looks for a .clang-format file by traversing the parent folders of the file (or so I understood from the documentation). Since we go in another root altogether the .clang-format file is not found.