Shebang error parsing: compatibility with tsc (#153)

Author: sandersn

internal/scanner/scanner.go

@@ -730,13 +730,13 @@ func (s *Scanner) Scan() ast.Kind {
 			if s.charAt(1) == '!' {
 				if s.pos == 0 {
 					s.pos += 2
-					for s.char() >= 0 && s.char() != '\n' {
-						s.pos++
+					for ch, size := s.charAndSize(); size > 0 && !stringutil.IsLineBreak(ch); ch, size = s.charAndSize() {
+						s.pos += size
 					}
 					continue
 				}
 				s.errorAt(diagnostics.X_can_only_be_used_at_the_start_of_a_file, s.pos, 2)
-				s.pos += 2
+				s.pos++
 				s.token = ast.KindUnknown
 				break
 			}