forwardslash error with myst init --write-toc

[FreekPols]

Description

With automatically building the toc (myst init --write-toc) I get a backslash in folder structure (e.g. chapters\h1.md) In building the output with gh, this output is not displayed as it needs a forwardslash (e.g. chapters/h1.md). Not tested with JB2 whether this is the case

Proposed solution

change \ into / when automatically building toc.