Parsing exceptions from Acorn for directives not correctly mapped to row/column

[Conduitry]

See e.g. https://svelte.technology/repl?version=2.14.0&gist=16755c91f5a1bb2bf2a587b1aa72e347

The error is displayed as being on line 1 column 80, when it is in fact at character 80.

cc @TehShrike

[Conduitry]

Aha - well this seems fishy!

[Conduitry]

PR incoming

[Conduitry]

Submitted PR and updated issue title - afaict, this only applies to expressions in directives, not elsewhere