Consistent parameter references and BigQuery terminology layout

What are you changing in this pull request and why?

Format BigQuery terminology paragraph as info block (as is consistent with other pages) and refer to parameter names without : suffix.

[x] I have reviewed the Content style guide so my content adheres to these guidelines.
[x] The topic I'm writing about is for specific dbt version(s) and I have versioned it according to the version a whole page and/or version a block of content guidelines.
[x] I have added checklist item(s) to this list for anything anything that needs to happen before this PR is merged, such as "needs technical review" or "change base branch."