Add highlight methods to search and search builder

[alexander-schranz]

This will add the core highlight methods for the highlighting search results:

$searchBuilder
    ->addIndex('blog')
    ->addFilter(new Condition\SearchCondition('Test'))
    ->highlight(
        fields: ['title', 'description'],
        preTag: '<mark>',
        postTag: '</mark>',
    )

See also #343

TODO implementation

• Add highlight methods to search and search builder #348
• Add testSearchConditionWithHighlight to AbstractSearcherTestCase: Add highlight implementation for memory adapter #351
• Memory: Add highlight implementation for memory adapter #351
• Elasticsearch
• Opensearch
• Meilisearch
• Algolia
• Redisearch: Add highlight implementation for redisearch adapter #355
• Typesense: Add highlight implementation for typesense adapter #354
• Solr: Add highlight implementation for solr adapter #353
• Loupe

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fixes #343