updateCase : Ref Ctxt Defs => Ref Syn SyntaxInfo => Ref ROpts REPLOpts => List ClauseUpdate -> Int -> Int -> Core (List String)Given a list of updates and a line and column, find the relevant line in
the source file and return the lines to replace it with.
getClause : Ref Ctxt Defs => Ref MD Metadata => Ref ROpts REPLOpts => Int -> Name -> Core (Maybe String)