Added line numbers to DSLParser errors

Change-Id: I895c3d94c9a49cc0350b287d3aa722050b91295e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/443036
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: John Stiles <johnstiles@google.com>
24 files changed