chore: deprecate rxjs-x/macro

[JasonWeinzierl]

The babel-plugin-rxjs-tools package is unmaintained (and never left prerelease). This PR deprecates the lint rule requiring use of that package.

If there are no objections, this rule will be removed before the release of v1.

[github-actions]

LCOV of commit 2888441 during .github/workflows/ci.yml #44

Summary coverage rate:
  lines......: 96.3% (3277 of 3404 lines)
  functions..: 93.0% (198 of 213 functions)
  branches...: 91.2% (620 of 680 branches)

Files changed coverage rate:
                                         |Lines       |Functions  |Branches    
  Filename                               |Rate     Num|Rate    Num|Rate     Num
  =============================================================================
  src/rules/macro.ts                     | 100%     64| 100%     5| 100%     10