## Because
- The `dedent` npm package is one more dependency for one small job. FXA-13426 asks us to cut dependencies.
- The swagger docs are the only code in `fxa-auth-server` that uses it.
## This pull request
- Adds a local tagged template at `docs/swagger/shared/dedent.ts` and drops the `dedent` dependency.
- Points the 17 swagger API modules and `shared/descriptions.ts` at the local helper.
- Adds `docs/swagger/shared/dedent.spec.ts` with 8 cases, and brings `docs/swagger` into `jest.config.js` and `tsconfig.json`.
- Expands the `\n` escape per raw template segment through a placeholder, so a literal `\n` from an interpolated value stays literal. A regression test covers it.
- Counts a non-blank line at column 0 in the indent scan, so a template that starts at column 0 keeps the indentation of the lines below it. A regression test covers it.
## Issue that this pull request solves
Closes: https://mozilla-hub.atlassian.net/browse/FXA-13930