fixup! fixup! fixup! Add DataFrame constructor for AnnData

Author: jdm204

docs/src/objects.md

@@ -87,8 +87,7 @@ By default, the first column `obs` corresponds to the `obs_names` and the remain
 
 To use a different data matrix (the default is `ad.X`), pass the name of the layer:
 
-```@example 1
-using DataFrames # hide
+```julia
 DataFrame(ad, layer="raw")
 ```