option "merge search results from the same line" is not effective on Scala + metaLS

[tribbloid]

here is a screenshot that illustrates the defect.

all "ArgNode" are from the same line, they should be merged.

I would also prefer that search result from both LSP and language plugin to be also merged

[angelozerr]

Indeed it should be nice but I fear that I will not have time to do that, any contribution are welcome!