C#: Re-factor order of usings.

[michaelnebel]

In this PR we introduce the following standard for using statements in our C# extractor source code files.
The order is

• System* (the standard library).
• Third party libraries (eg. Microsoft.CodeAnalysis).
• Semmle* (out own namespaces), starting with Semmle.Util* (the remaining is in alphabetical order)
• Type abbreviations (using X = Y).

Unit test projects follows the same pattern except that the first using statement is using Xunit.

[hvitved]

Is there a VS code plugin to enforce this?

[michaelnebel]

Is there a VS code plugin to enforce this?

That is a really good question (I didn't use any when doing the rearrangement)!
I found C# Format Usings which helps quite a lot (using the following sort order: Xunit System Microsoft Semmle.Util Semmle). It requires that you execute Format Usings on the file where you want re-format.

[michaelnebel]

@hvitved : Added the C# Format Usings as recommended plugin: #14015