Fix Lsif transformer for C-lang
LSIF file for C-lang contains multiple contains
entries:
{"id":48,"type":"edge","label":"contains","outV":9,"inVs":[47]}
...
{"id":60,"type":"edge","label":"contains","outV":9,"inVs":[59]}
instead of a single one:
{"id":48,"type":"edge","label":"contains","outV":9,"inVs":[47, 59]}
Let's accumulate contains references instead of overriding them: #305 (closed)