Fix backslash bugs in convert feature

[ong6]

What is the purpose of this pull request?

• Documentation update
• Bug fix
• Feature addition or enhancement
• Code maintenance
• Others, please explain:

Fixes #1736

Overview of changes:

Updated the relativePagePath to ensure that no unnecessary \ were being made. Done by updating a function from fsUtil

Anything you'd like to highlight / discuss:

Testing instructions:

Run markbind init -convert on a test repo and make sure there are no instances of \ or %5C in the layouts/default.md file.
Build and see that there also should not have any instance of \ or %5C

Proposed commit message: (wrap lines at 72 characters)

Resolved bug regarding backslashes in convert feature

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Checklist: ☑️

• Updated the documentation for feature additions and enhancements
• Added tests for bug fixes or features (will be done in another PR)
• Linked all related issues
• No unrelated changes

[jonahtanjz]

Saw that in one of the commits you updated the package-lock.json. Is there a reason for that?

Otherwise, LGTM 👍

[ong6]

Saw that in one of the commits you updated the package-lock.json. Is there a reason for that?

Otherwise, LGTM 👍

I thought my package-lock.json was failing the Appveyor build. But then realized it was another issue altogether. Also, I think zeyu asked me to remove some lines from the PR #1727.

[jonahtanjz]

Thanks for clarifying @ong6 :)

[ang-zeyu]

I thought my package-lock.json was failing the Appveyor build. But then realized it was another issue altogether. Also, I think zeyu asked me to remove some lines from the PR #1727.

#1727 (comment) Sorry for the ambiguous wording.

To clarify, I meant removing the diffs. (same rationale as #1679 (comment))

fyi, the issue with appveyor: https://github.com/actions/setup-node/issues/411
I think we can make a mental note of testing the windows build locally for now and ignore the failing builds @jonahtanjz @ryoarmanda

[ang-zeyu]

I've reverted the package-lock changes from #1728, which seems to be causing the changes here.
You can remove the diffs by merging in the latest changes too :)