Add . to end of auto-generated GraphQL docs

What does this MR do?

This MR changes the descriptions under the type and enum headings in our auto-generated GraphQL docs to end with a ..

It also removes a few occurrences of there being .s added to the end of the description strings of the types or enums, to avoid double-.s, and to make these strings consistent.

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done