[MERGE][0.17] sanitize developers docs

[Ian Clatworthy]

Aaron Bentley wrote:

> @@ -1,5 +1,5 @@
>  Bundle Creation
> -===============
> +---------------
> 
> ^^^^^^^^^^ we probably also need to standardize our heading order, since
> ReST doesn't.  But I find it counterintuitive for "===" to be less
> significant than "---".

I agree. I'd rather see the counter intuitive docs fixed than adopt a
convention that feels wrong. Thanks for suggesting an order though.

Ian C.