Find another check for merger

[HannahFromAland]

Hi everyone, I came across a new checkpoint this morning when merging the #56.
The chapter name (the single hashtag line in .Rmd file, aka first line) cannot have . in it.

For example, in #56 the original chapter name was shown as:
but the workflow failed
It worked after I revise the data.table into datatable. (since the chapter name will also be web name which will have .html as ending, using . in name will cause error)

Maybe it can be added into our tutorials as a checkpoint

[jtr13]

Good sleuthing... I haven't seen that before. Perhaps we can add a second heading to include data.table -- since it's the package name we can't really change it

# Different methods for handling data in R

## A comparison of base R, tidyverse, and data.table