Move the following diagnostics into static readonly fields: GD0101, GD0102, GD0103, GD0104, GD0105, GD0106, GD0107, GD0201, GD0202, GD0203, GD0301, GD0302, GD0303, GD0401, GD0402.
To be more consistent, the titles for the following diagnostics were modified: GD0101, GD0105, GD0106, GD0302, GD0303, GD0401, GD0402. A subsequent update of the documentation repo is needed.
Tests for the following diagnostics were created: GD0201, GD0202, GD0203.