row_spec arguments hline_after and extra_latex_after inserting space between rows in package version 1.4.0

[k96nb01]

Describe the bug
The row_spec arguments to introduce lines in a table now also insert space in version 1.4.0

library(kableExtra)

kbl(mtcars[1:5, 1:5], "latex", booktabs = TRUE) %>% row_spec(2, extra_latex_after = "\\cline{2-6}") %>% row_spec(4, hline_after = TRUE)

Output version 1.3.4:

Output version 1.4.0:

[dmurdoch]

The problem is that the output Latex looks like this:

\begin{tabular}[t]{lrrrrr}
\toprule
  & mpg & cyl & disp & hp & drat\\
\midrule
Mazda RX4 & 21.0 & 6 & 160 & 110 & 3.90\\
Mazda RX4 Wag & 21.0 & 6 & 160 & 110 & 3.90\\
\cline{2-6}\\
Datsun 710 & 22.8 & 4 & 108 & 93 & 3.85\\
Hornet 4 Drive & 21.4 & 6 & 258 & 110 & 3.08\\
\midrule\\
Hornet Sportabout & 18.7 & 8 & 360 & 175 & 3.15\\
\bottomrule
\end{tabular}

Those \\ line breaks in \cline{2-6}\\ and \midrule\\ shouldn't be there, and weren't there in 1.3.4.