Except `csv.gz`, no compression for `.gz` extensions

[chainsawriot]

## fwrite can do this automatically, so this is a special case
R.utils::isGzipped(rio::export(iris, tempfile(fileext = ".csv.gz")), method = "content")
#> [1] TRUE

## But not this
R.utils::isGzipped(rio::export(iris, tempfile(fileext = ".ods.gz")), method = "content")
#> [1] FALSE

## It is still vanilla ODS; with no gz compression
readODS::read_ods(rio::export(iris, tempfile(fileext = ".ods.gz")))
#> # A tibble: 150 × 5
#>    Sepal.Length Sepal.Width Petal.Length Petal.Width Species
#>           <dbl>       <dbl>        <dbl>       <dbl> <chr>  
#>  1          5.1         3.5          1.4         0.2 setosa 
#>  2          4.9         3            1.4         0.2 setosa 
#>  3          4.7         3.2          1.3         0.2 setosa 
#>  4          4.6         3.1          1.5         0.2 setosa 
#>  5          5           3.6          1.4         0.2 setosa 
#>  6          5.4         3.9          1.7         0.4 setosa 
#>  7          4.6         3.4          1.4         0.3 setosa 
#>  8          5           3.4          1.5         0.2 setosa 
#>  9          4.4         2.9          1.4         0.2 setosa 
#> 10          4.9         3.1          1.5         0.1 setosa 
#> # ℹ 140 more rows

^{Created on 2024-04-26 with reprex v2.1.0}