Documentation is missing for various calls

[DeniseSl22]

Please write documentation for the following calls:

• https://github.com/openphacts/ops.js/blob/master/src/MapSearch.js

@egonw

[marvinm2]

• https://github.com/openphacts/ops.js/blob/master/src/ConceptWikiSearch.js line 97: findCompounds

• https://github.com/openphacts/ops.js/blob/master/src/ConceptWikiSearch.js line 125: findTargets

• https://github.com/openphacts/ops.js/blob/master/src/ConceptWikiSearch.js line 152: findConcept

• https://github.com/openphacts/ops.js/blob/master/src/PathwaySearch.js line 307: byReference

• https://github.com/openphacts/ops.js/blob/master/src/PathwaySearch.js line 341: countPathwayByReference

• https://github.com/openphacts/ops.js/blob/master/src/PathwaySearch.js line 367: getReferences

• https://github.com/openphacts/ops.js/blob/master/src/StructureSearch.js All

• https://github.com/openphacts/ops.js/blob/master/src/TreeSearch.js All