Clarify patternType logic
Created by: attfarhan
Fixes https://github.com/sourcegraph/sourcegraph/issues/8161. Added some clarification in the code comments that exist regarding how patternType is set, and added notes in the changelog.
Created by: attfarhan
Fixes https://github.com/sourcegraph/sourcegraph/issues/8161. Added some clarification in the code comments that exist regarding how patternType is set, and added notes in the changelog.