Handle SyntaxErrors in a slightly smarter way

SyntaxErrors are strange and mystical beasts. On top of the problems we
encountered previously in GitLab#237, it's now apparent that
SyntaxErrors can also occur across multiple lines (in fact, across the
rest of a file). In the event of a "multi-line" SyntaxError, we need to
determine what row to report and what the column number is.

For now, we're going to use the row number of the first line and limit
the column number to be less than the end of the line. It may not be
perfect, but it is slightly better.

Related-to #237
Closes #259