`@block` imports are too sensitive about missing semicolons

## Expected
Semicolons should be optional at the end of `@block` import lines. Ex:

## Actual
Throws a confusing lookup path error because the parser does not consider `\n` to be a terminating char. Following lines are accidentally considered part of the file path.

Locate the parser handling `@block` import lines and reproduce an import without a trailing semicolon. Check how newline characters terminate the file path, then add coverage for the semicolon-optional form and confirm that following lines are no longer included in lookup errors.

Written by the indexing model from the issue text.