Problem

When the serde feature is enabled on ratatui, it doesn't enable the serde feature on the re-exported crossterm.

Solution

Enabling the serde feature on ratatui should automatically enable crossterm's serde feature on the re-exported version.

Alternatives

Adding feature flags for backend features as suggested in #1319 would work, since then there would just be a separate feature for crossterm serde that could be enabled. This would be somewhat less ergonomic/intuitive though, since you would have to enable two different serde features to actually get serde on everything that supports it.