Add note about document submission operations

[theromulans]

TAX-100

What changed?

• Added a note about document submission operations directly within our API reference.

We keep getting tax providers miss this key detail, so we're hoping this change helps reduce the number of these questions.

"Note" style is lifted from the nearby Tax Provider Connection API documentation.

Related docs: https://developer.bigcommerce.com/docs/rest-contracts/tax

[jvpcode]

This suggestion might be overkill, but what do you think about instead (or in addition) adding a similar note/s to the table with the details an integrator needs to provide us? i.e. the table here: https://developer.bigcommerce.com/docs/integrations/tax#sharing-provider-details-with-bigcommerce

My perspective is:

• Tax integrator wants to add a tax provider
• Looks at the details they need to provide
• Looks at the description for commit/void/adjust URLs
• Sees in the description for adjust (as an example)

URL BigCommerce should use for Tax Provider API quote requests. [Document submission](/docs/integrations/tax#document-submission) operations are only triggered when the *Submit Order Data* provider setting is enabled.

That way (hopefully) the integrator is hopefully already having that setting in mind when they send us the details to begin with