search: export TextSearchRequest
requested to merge backend-dry-run/rvt/native-zoekt-and-4 into backend-dry-run/rvt/native-zoekt-and-33
Created by: rvantonder
Stacked on https://github.com/sourcegraph/sourcegraph/pull/24179. Prep for next PR which will call this outside of the unindexed package for structural search.