Possiblity to include markdown files

[OskarKlintrot]

Is the feature request related to a problem

I'm trying to switch from SourceTransform to InPlaceOverwrite but I ran into an issue. ValidateContent now errors out on some markdown files I'm not interested in (some README.md for test projects etc). I'm only interested for MarkdownSnippets to work it's magic on the md-files in \Docs\DocFx\articles but still looking for snippets in \. There are some md-files here and there making it a bit cumbersome to exclude them all.

Describe the solution

"IncludeMarkdownDirectories": [ "\\Docs\\DocFx\\articles" ]

Describe alternatives considered

"ExcludeMarkdownDirectories": [ "A", "Whole", "Bunch", "Of", "Directories" ]

Additional context

~~I'm not sure what #120 is but it sounds like it could be this. That feature seems to have been removed.~~ Nope, it wasn't.

[SimonCropp]

can u share a failing unit test as a Pull Request

[OskarKlintrot]

Sure, just give me a few days!