Update .editorconfig

[Youssef1313]

This update matches the current dotnet/runtime .editorconfig file. I'll point to the most obvious problems that was in the .editorconfig here.

[wli3]

This is the same as the one in dotnet runtime?

[Youssef1313]

This is the same as the one in dotnet runtime?

Yes, Only changed the header template (in the second commit) to match the one used here.

[Youssef1313]

If a forgotten file extension isn't included in .editorconfig, it may use indent_size = 4 by mistake. I think it makes more sense to move this option to .cs and .vb files only.

For example, the .editorconfig existed before this PR didn't include yml extensions. So, it will use 4 spaces by default, where it should use only 2.

It's more robust to set it only to cs and vb.

[wli3]

@Youssef1313 I'll take this change after you revert trim_trailing_whitespace change, since you put a lot thought into. However, it is better to change the file in dotnet/runtime too. Since we don't really want to make a separate style for dotnet/sdk. The next time we sync the file with dotnet/runtime would remove all the special change you made this time.

[Youssef1313]

it is better to change the file in dotnet/runtime too.

I opened a discussion in dotnet/runtime.