implement PrettyError for DrawError

[Wumpf]

Description
Given for example a LateMinBufferBindingSizeMismatch error:

In a RenderPass
      note: encoder = `egui_webpainter_paint_and_update_textures`
    In a draw command, indexed:false indirect:false
      note: render pipeline = `<RenderPipeline-(1, 1, Gl)>`
    Buffer is bound with size 16 where the shader expects 32 in group[0] compact index 0

.. then the inner DrawError is not pretty printed