Bug fixes

Updating Drupal core to 8.6.15

Issue #2915422 by lussoluca: Swiftmailer configuration cannot be set
Issue #2954130 by kim.pepper, Sam152, zaporylie: Mitigate huge values for $context due to core adding backtrace information to logs
Issue #3038575 by slip: Logging level parameters in README should be wrapped in %s
Issue #2749859 by pdenooijer, Eyal Shalev: Logger channel factory must return instances of LoggerChannelInterface
Issue #2917402 by legolasbo: Prevent logging duplicate information
Issue #2935355 by Patrick Bauer: DrupalHandler ignores handler processors

Fixes missing HTML Class

This update contains new features as well as security updates for the following:
- Core 7.65 -> 7.66
- Module filter 2.0 -> 2.2

New features

Search - More control over important results

You can now boost the importance of particular content in the search results by making them promoted. This can be achieved by editing the content and then on the bottom going to the publishing options and check “sticky at top of list”.
Note that this requires a re-index of the search, otherwise it won’t show.