Set lintr for linting R codes

[eitsupi]

Addresses #169.

A series of fixes resolved all but one error.

> lintr::lint_package()
.......................................
R/sanitize_code.R:25:1: style: [cyclocomp_linter] Functions should have cyclomatic complexity of less than 15, this has 16.
fill_block_comments <- function(lns, fill_with = " ") {
^

All errors can be corrected by refactoring the fill_block_comments function or allowing this in the rules.

• For objects used only as strings in glue::glue like functions, lintr is not detectable, so the # nolint comment has been used.
• object_name_linter was turned off because functions that mix underbars and dots are not allowed in lintr.
• commented_code_linter was turned off because there is quite a lot of code in the comments.

@Ilia-Kosenkov Sorry to I do this even though you are the assignee of #169. Feel free to edit this PR.

[eitsupi]

All errors can be corrected by refactoring the fill_block_comments function or allowing this in the rules.

Curiously, the last commit did not raise this error. The lint workflow is now green.

[Ilia-Kosenkov]

By all means, feel free to take a shot at any issue, or create your own issues for discussion. No hard feelings here. fill_block_comment() is indeed quite large, but it is the cost of not using any third-party parsers for rust code (and thus keeping the package purely R). It can be reworked for sure (and there are lots of typos in the comments that can be fixed). Let's open an issue for this and fix it separately.

Otherwise, great job! If you are ready, mark this PR as ready for review & I'll merge it

[eitsupi]

Thanks. I think you can merge this as the work I can do seems to be complete.