Fix creation of new child page

[deining]

This PR ...

• Fixes Create a new child page doesnt work. #1637
• Fixes create child page should not include the "parent" filename in the GH repo path as it breaks github's preview tab #668
• Closes Resolves the breaks in github's preview tab #1488

[chalin]

💛

[chalin]

I think that this feature is misnamed. I'll file an issue explaining what I mean.

[chalin]

I think that this feature is misnamed. I'll file an issue explaining what I mean.

See:

• Create-page feature can create either a child or a sibling page -- consider name and doc updates #1647

[chalin]

@deining - btw, I'd generally avoid putting a fixed issue number at the end of the PR title for two reasons:

• When we merge, GH suffixes the title with the PR number and so, in the case of this PR, we'd end up with a commit title having suffix "(Create a new child page doesnt work. #1637) (Fix creation of new child page #1644)" ... which IMHO is confusing.
• It's is common enough that PR's fix more than one issue and contribute to others. In such a case it doesn't make sense to select just one issue to put in the PR title.

My 2 cents. If you feel strongly about it, maybe put the issue number at the start, so we'd end up with commit log titles like "[#1637] Fix ... (#1644)"? Just a thought.