Remove trailing slash for typescript and python scrubbing directories

[matthewgeng]

Notion ticket link

No ticket. Was originally part of fixing the RM bug, but that was moved to backlog.

Implementation description

• Removed a trailing slash for the scrubbing of typescript and python directories

Steps to test

1. Run CLI until reaching the RM bug --> should be no double slash

What should reviewers focus on?

Checklist

• My PR name is descriptive and in imperative tense
• My commit messages are descriptive and in imperative tense. My commits are atomic and trivial commits are squashed or fixup'd into non-trivial commits
• I have run the appropriate linter(s)
• I have requested a review from the PL, as well as other devs who have background knowledge on this PR or who will be building on top of this PR
• I have updated the version number in package.json according to Semantic Versioning specs (semver) if I will be publishing these changes to the npm registry

[sherryhli]

Looks good, but please edit the PR title to something along the lines of "Remove trailing slash in directory names"

[sherryhli]

May need to bump package version to 1.0.19 depending on if #33 is merged first