Switch to material theme for docs
Switch to material theme for docs

There's numerous issues with the formatting in the readthedocs
theme. Material is far from perfect but it displays the docs
in a more readable format.

This is a short term fix on the way to a theme that works better
for the Pony standard library docs.

CausalityLtd/ponyc,Theodus/ponyc,boemmels/ponyc,jemc/ponyc,mkfifo/ponyc,ponylang/ponyc,kulibali/ponyc,Praetonus/ponyc,mkfifo/ponyc,jupvfranco/ponyc,lukecheeseman/ponyta,ryanai3/ponyc,Perelandric/ponyc,cquinn/ponyc,jupvfranco/ponyc,dipinhora/ponyc,jupvfranco/ponyc,jupvfranco/ponyc,kulibali/ponyc,jupvfranco/ponyc,CausalityLtd/ponyc,Theodus/ponyc,Praetonus/ponyc,sgebbie/ponyc,sgebbie/ponyc,boemmels/ponyc,doublec/ponyc,Theodus/ponyc,Theodus/ponyc,kulibali/ponyc,lukecheeseman/ponyta,jemc/ponyc,malthe/ponyc,kulibali/ponyc,sgebbie/ponyc,Perelandric/ponyc,Perelandric/ponyc,ponylang/ponyc,jemc/ponyc,dipinhora/ponyc,cquinn/ponyc,ponylang/ponyc,boemmels/ponyc,boemmels/ponyc,Perelandric/ponyc,ryanai3/ponyc,boemmels/ponyc,sgebbie/ponyc,Praetonus/ponyc,CausalityLtd/ponyc,dipinhora/ponyc,doublec/ponyc,mkfifo/ponyc,mkfifo/ponyc,sgebbie/ponyc,malthe/ponyc,lukecheeseman/ponyta,Theodus/ponyc,malthe/ponyc,cquinn/ponyc,mkfifo/ponyc,cquinn/ponyc,ryanai3/ponyc,Perelandric/ponyc,Praetonus/ponyc,doublec/ponyc,malthe/ponyc