If you are just interested in installing the docset (and not in building it yourself), just click here to install the docset. This docset is bundled as a user contribution with Dash, which is updated regularly, but the link above will always get you the latest version.
To install the prerequisites, run
git submodule update --init npm install
To build the docset, run
npm run build
This will create a
build directory with all build results.
Use the resulting docset by adding the
.docset to the Docsets tab of Dash.
The build command also generates a Dash feed in
.html file in the
feed dir contains the Dash URL,
which will install the docset when it is opened.