Better conversion to quickfix list

[Natr1x]

Is your feature request related to a problem? Please describe.
I would like to be able use telescope to filter my quickfix and location list but a lot of information is lost when sending to the quickfix list.
Diagnostics will for example discard end_lnum and end_col.

Describe the solution you'd like
Ideally I would like the action of sending entries to the quickfix list or location list to send all compatible fields of the entry.
I e if the entry has an end_lnum field then that would be copied to the quickfix entry.

I am unsure if valid and vcol should be copied directly however or some new field name should be introduced for them.

Lastly the whole entry would then be placed as is inside user_data. This way you would not lose any entry information when sending it to the quick.

Describe alternatives you've considered
An alternative solution would be to add something like an "telescope_entry_source_id" field to the user_data.

This would give plugins which want to make use of both telescope and the quicklist to handle quicklist entries differently depending on where they came from. I e If it is known that a quickfix entry was added by telescope from diagnostics then a plugin could retreive end_lnum and end_col and add them back themselves.

This would make on the fly usage a more complicated though since you wouldn't be able to just loop through and inspect the user_data but instead look up the documentation on a case by case basis.