Add a markdown format checker

[cansavvy]

Is your feature request related to a problem? Please describe.

I frequently have markdown related formatting mistakes like:

Where Cancer Models should have been on the next line and I didn't realize it wasn't.

Describe the solution you'd like

I want an automatic checker that looks for obvious markdown formatting mistakes like this.

Although such a thing wouldn't catch everything, it might do a good job catching a lot of them and it's worth a try.

Describe alternatives you've considered

I need to look into whether something like this that is compatible for OTTR already exists,

Additional context

Really this would end up living on the ottr-reports repo as another check like spell check or etc