Explore making indexing locations lazily fetched with comments

Currently, we eagerly capture all entry locations in the index. We may be able to improve both performance and memory usage if we delay that to only when entries are interacted with.

Entries already know which file they were discovered in and we already fetch their comments lazily, so we could very well build the indexer locations lazily too. Something like

class Entry
  def comments
    return @comments if @comments

    fetch_lazy_data!
    @comments
  end

  def location
    return @location if @location

    fetch_lazy_data!
    @location
  end

  private

  def fetch_lazy_data!
    parse_result = Prism.parse_file(@file_path)

    # Figure out the location for this entry
    # Figure out comments
    # Other things we fetch lazily
  end
end

Start by tracing the Entry indexing path and the existing lazy comments handling, then inspect where indexer locations are eagerly captured. Use Prism.parse_file and the Entry location/comments entry points as the comparison boundary; done means the proposal is evaluated with behavior preserved and its performance and memory impact demonstrated.