[README] Tweak example usage instructions
Don't use the `env.benchmark` attribute, and use active writing
style.
@@ -175,12 +175,14 @@ In Python, import `compiler_gym` to use the environments:
```py
>>> import gym
->>> import compiler_gym # imports the CompilerGym environments
->>> env = gym.make("llvm-autophase-ic-v0") # starts a new environment
->>> env.benchmark = "benchmark://cbench-v1/qsort" # select a program to compile
->>> env.reset() # starts a new compilation session
->>> env.render() # prints the IR of the program
->>> env.step(env.action_space.sample()) # applies a random optimization, updates state/reward/actions
+>>> import compiler_gym # import the CompilerGym environments
+>>> env = gym.make( # create a new environment
+... "llvm-autophase-ic-v0" # select the compiler optimization task
+... benchmark="cbench-v1/qsort" # select the program to compile
+... )
+>>> env.reset() # start a new compilation session
+>>> env.render() # print the IR of the program
+>>> env.step(env.action_space.sample()) # apply a random optimization, update state/reward/actions
```
See the [documentation website](http://facebookresearch.github.io/CompilerGym/)
