Consistent chainable mutator behavior (#295)

src/Aggregation/Metric/PercentilesAggregation.php

src/Aggregation/Metric/ScriptedMetricAggregation.php

src/Aggregation/Metric/TopHitsAggregation.php

src/Aggregation/Pipeline/AbstractPipelineAggregation.php

src/Aggregation/Pipeline/BucketScriptAggregation.php

src/Aggregation/Pipeline/BucketSortAggregation.php

src/Aggregation/Pipeline/PercentilesBucketAggregation.php

src/FieldAwareTrait.php

src/NameAwareTrait.php

src/ParametersTrait.php

src/Query/Span/FieldMaskingSpanQuery.php

src/Query/Span/SpanContainingQuery.php

src/Query/Span/SpanNearQuery.php

src/Query/Specialized/TemplateQuery.php

src/ScriptAwareTrait.php

src/Search.php

src/Sort/FieldSort.php

src/Sort/NestedSort.php

src/Suggest/Suggest.php