Make clearer that file resources that are used as key trust material
are polled and will be reloaded upon modification.

* 6.x:
  Mute test watcher usage stats output
  [Rollup] Fix FullClusterRestart test
  TEST: Disable soft-deletes in ParentChildTestCase
  TEST: Disable randomized soft-deletes settings
  Integrates soft-deletes into Elasticsearch (#33222)
  drop `index.shard.check_on_startup: fix` (#32279)
  Fix AwaitsFix issue number
  Mute SmokeTestWatcherWithSecurityIT testsi
  [DOCS] Moves ml folder from x-pack/docs to docs (#33248)
  TEST: mute more SmokeTestWatcherWithSecurityIT tests
  [DOCS] Move rollup APIs to docs (#31450)
  [DOCS] Rename X-Pack Commands section (#33005)
  Fixes SecurityIntegTestCase so it always adds at least one alias (#33296)
  TESTS: Fix Random Fail in MockTcpTransportTests (#33061) (#33307)
  MINOR: Remove Dead Code from PathTrie (#33280) (#33306)
  Fix pom for build-tools (#33300)
  Lazy evaluate java9home (#33301)
  SQL: test coverage for JdbcResultSet (#32813)
  Work around to be able to generate eclipse projects (#33295)
  Different handling for security specific errors in the CLI. Fix for #33230 (#33255)
  [ML] Refactor delimited file structure detection (#33233)
  SQL: Support multi-index format as table identifier (#33278)
  Enable forbiddenapis server java9 (#33245)
  [MUTE] SmokeTestWatcherWithSecurityIT flaky tests
  Add region ISO code to GeoIP Ingest plugin (#31669) (#33276)
  Don't be strict for 6.x
  Update serialization versions for custom IndexMetaData backport
  Replace IndexMetaData.Custom with Map-based custom metadata (#32749)
  Painless: Fix Bindings Bug (#33274)
  SQL: prevent duplicate generation for repeated aggs (#33252)
  TEST: Mute testMonitorClusterHealth
  Fix serialization of empty field capabilities response (#33263)
  Fix nested _source retrieval with includes/excludes (#33180)
  [DOCS] TLS file resources are reloadable (#33258)
  Watcher: Ensure TriggerEngine start replaces existing watches (#33157)
  Ignore module-info in jar hell checks (#33011)
  Fix docs build after #33241
  [DOC] Repository GCS ADC not supported (#33238)
  Upgrade to latest Gradle 4.10  (#32801)
  Fix/30904 cluster formation part2 (#32877)
  Move file-based discovery to core (#33241)
  HLRC: add client side RefreshPolicy (#33209)
  [Kerberos] Add unsupported languages for tests (#33253)
  Watcher: Reload properly on remote shard change (#33167)
  Fix classpath security checks for external tests. (#33066)
  [Rollup] Only allow aggregating on multiples of configured interval (#32052)
  Added deprecation warning for rescore in scroll queries (#33070)
  Apply settings filter to get cluster settings API (#33247)
  [Rollup] Re-factor Rollup Indexer into a generic indexer for re-usability   (#32743)
  HLRC: create base timed request class (#33216)
  HLRC: Use Optional in validation logic (#33104)
  Painless: Add Bindings (#33042)