Issue #2320245 by benjy | jhodgdon: Fixed High water should consistently be two words.

core/modules/migrate/src/Entity/Migration.php

core/modules/migrate/src/Entity/MigrationInterface.php

core/modules/migrate/src/MigrateExecutable.php

core/modules/migrate/src/Plugin/migrate/source/SqlBase.php

core/modules/migrate/src/Source.php

core/modules/migrate/tests/src/MigrateSqlSourceTestCase.php

...ts/src/source/VariableMultiRowSourceWithHighwaterTest.php

.../modules/migrate_drupal/tests/src/source/VariableTest.php

...al/tests/src/source/d6/CommentSourceWithHighwaterTest.php

...s/migrate_drupal/tests/src/source/d6/FilterFormatTest.php

...dules/migrate_drupal/tests/src/source/d6/TermTestBase.php

...dules/migrate_drupal/tests/src/source/d6/UrlAliasTest.php