[R-package] [docs] Simplified examples to cut example run time (fixes #2988)#2989

Merged

StrikerRUS merged 3 commits intomicrosoft:masterfrom jameslamb:misc/r-example-times

Apr 15, 2020

+132-124

Commits on Apr 10, 2020

[R-package] [docs] Simplified examles to cut example run time (fixes microsoft#2988 )
jameslamb
committed

Commits on Apr 13, 2020