[R] Update docs about applicability of learning_rate
#13851
| Job | Run time |
|---|---|
| 13m 13s | |
| 3m 6s | |
| 10m 17s | |
| 10m 7s | |
| 11m 7s | |
| 13m 23s | |
| 3m 7s | |
| 3m 30s | |
| 4m 32s | |
| 6m 59s | |
| 4m 40s | |
| 9m 1s | |
| 2m 57s | |
| 17m 57s | |
| 1m 34s | |
| 1h 55m 30s |