Match preference should be given to whole word over individual parts

For example, if searching for DiffBlock, preference should be given to the word DiffBlock versus words that contain only Diff or Block.

This should work both when search terms use the operator "and" as well as "or"

Currently, it seems that since the search is breaking these up, the individual parts are checked, versus checking the whole.

Start by locating the Java search-term parsing and matching entry points, especially where terms are split into parts. Reproduce the DiffBlock case with both the "and" and "or" operators; done means whole-word matches receive preference over matches containing only Diff or Block.

Written by the indexing model from the issue text.