[Bug]: [Doc] Beam Capability Matrix space

### What happened?

https://beam.apache.org/documentation/runners/capability-matrix/unbounded-splittable-dofn-support-status/ (and similar) require a lot of scrolling to view, with a lot of empty space. We could make this much more compact. On that note, https://beam.apache.org/documentation/runners/capability-matrix/ could be augmented with tool tips so one could see the details in, e.g., the "partially supported" boxes by hovering over them.

### Issue Priority

Priority: 2 (default / most bugs should be filed as P2)

### Issue Components

- [ ] Component: Python SDK
- [ ] Component: Java SDK
- [ ] Component: Go SDK
- [ ] Component: Typescript SDK
- [ ] Component: IO connector
- [ ] Component: Beam examples
- [ ] Component: Beam playground
- [ ] Component: Beam katas
- [X] Component: Website
- [ ] Component: Spark Runner
- [ ] Component: Flink Runner
- [ ] Component: Samza Runner
- [ ] Component: Twister2 Runner
- [ ] Component: Hazelcast Jet Runner
- [ ] Component: Google Cloud Dataflow Runner