Detect if a line is within a multi-line comment block

[lingyuncai]

The detection is used multiple times in our codebase, and we could improve the detection for lines within a multi-line comment block. See examples below:

https://github.com/intel/webinizer/blob/f6c375223d2e80fff7e6bd8191fb0d2871ef31ef/src/advisors/cpp_exception.ts#L52-L57