Module to read specific lines from files. The data from any file will stay in memory until the handle is collected by the gc

`type t`````
`val create : unit ‑> t`

create a line reader

`val from_file_linenum_original : t ‑> InferBase.SourceFile.t ‑> int ‑> string option`

get the line from a source file and line number

`val from_loc : t ‑> InferBase.Location.t ‑> string option`

get the line from a location looking for the copy of the file in the results dir