Convert comments on function examples to /** */ style

[wilzbach]

From @stonemaster on May 13, 2016 7:1

As phobos does it all comments should have the /** and */ syntax for comments.

Copied from original issue: dlang-tour/core#43

[wilzbach]

There are also a couple of other Phobos style guidelines - like Allman braces Or spaces between import selections etc that we should look for and be consistent. Ideally we should run Dscanner on our code samples.

[wilzbach]

Okay I gave it a shot and didn't realize that there were so many different styles -> sorry about the noise :/