Test if a path is an absolute path
is_absolute_path(path)A character vector of one or more paths.
is_absolute_path("/foo")
#> [1] TRUE
is_absolute_path("C:\\foo")
#> [1] TRUE
is_absolute_path("\\\\myserver\\foo\\bar")
#> [1] TRUE
is_absolute_path("foo/bar")
#> [1] FALSE