This is the paste/clear vocabulary — what clear and copyFrom operate on, aligned to
Office Scripts (ClearApplyTo / RangeCopyType). It is deliberately not a union view
over Feature: its members name behaviors, not subsets — Values pastes a formula's
computed result (a transform), and Formats carries merge state as Excel's format painter
does. The read path (getCounts, isContentful, getRegions) selects by ICellRange.Feature.
Errors, Warnings and Merges left this enum with the getCounts realignment — they
were query vocabulary riding along (nothing pastes an error); querying is
ICellRange.Feature.Error / .Merge (warnings return with evaluated-state support).
Represents the types of content that can be associated with a cell or range.