0.9.1: Solr 9.7 compatibility, fixes

Changed

• During indexing, we now only need a single pass through the input files, instead of
  two, this is in preparation for the S3 storage backend, where we don't have the luxury
  of relying on a page cache to paper over our inefficencies.

Fixed

• Fix bug that resulted in missed matches during highlighting (#442, thanks @schmika!)
• Fix bug that resulted in incomplete reads from the input file under some circumstances (#441, thanks @schmika!)
• Compatibility with Solr 9.7