Elsbeth adds additional invisible classes

[gadenbuie]

Also .ace_invisible_tab, .ace_invisible_eol and .ace_invisible_space.

rsthemes/inst/templates/rstudio/_rstudio-dark.scss

Lines 155 to 157 in b93fc1f

	.ace_invisible {
	color: $ui_invisible;
	}

rsthemes/inst/templates/rstudio/_rstudio-light.scss

Lines 181 to 183 in b93fc1f

	.ace_invisible {
	color: $ui_invisible;
	}