feat(theme-docs): add defaultDir options

[benjamincanac]

This option can be used to override the default docs dir used in the "Edit this page on GitHub" link if your project lives in a different directory.

Types of changes

• Bug fix (a non-breaking change which fixes an issue)
• New feature (a non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Description

Resolves #455, resolves #430.

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes (if not applicable, please state why)

[kaka-ruto]

Looks good @benjamincanac . Thanks! (I should've taken this though 🤦‍♂️ )

[kaka-ruto]

@benjamincanac how about picking the argument passed onto create-nuxt-content-docs CLI and using that as the default docs dir name?

[benjamincanac]

@kaka-ruto The issue is that the default dir name is the current directory, so it would give wrong informations to defaultDir when doing yarn create nuxt-content-docs without a path.

[kaka-ruto]

Aaah, I see. This looks good then. Thanks @benjamincanac