Fix "histogram" feature to be all_series rather than all_elements

Author: fotonick

plotters/Cargo.toml

@@ -66,8 +66,8 @@ default = [
         "deprecated_items",  "all_series", "all_elements",
         "full_palette"
 ]
-all_series = ["area_series", "line_series", "point_series", "surface_series"]
-all_elements = ["errorbar", "candlestick", "boxplot", "histogram"]
+all_series = ["area_series", "line_series", "point_series", "surface_series", "histogram"]
+all_elements = ["errorbar", "candlestick", "boxplot"]
 
 # Tier 1 Backends
 bitmap_backend = ["plotters-bitmap", "ttf"]