Fix async Swift docs
Fix async Swift docs

Just use the same example from above. The timeout example (a) used a method that wasn't used anywhere else and (b) called `done()` at the wrong time. This clears it up and harmonizes the async examples!
abbeycode/Nimble,twobitlabs/Nimble,AnthonyMDev/Nimble,AnthonyMDev/Nimble,Quick/Nimble,twobitlabs/Nimble,DanielAsher/Nimble,DanielAsher/Nimble,Quick/Nimble,phatblat/Nimble,AnthonyMDev/Nimble,abbeycode/Nimble,DanielAsher/Nimble,twobitlabs/Nimble,Quick/Nimble,abbeycode/Nimble,phatblat/Nimble,abbeycode/Nimble,phatblat/Nimble