Fix typo in readme

[brson]

I thought maybe this was an intentional subtle joke, mimicking the two "g"s and "z"s in honggfuzz, but probably not.

[PaulGrandperrin]

Hi @brson, you guessed right, I think the only lame joke there is in the project is the inclusion of the WTFPL licencing :-)

Also, I just want to thank you for all the great work you did on the Rust ecosystem and I hope you found what you looked for when leaving Mozilla!

[PaulGrandperrin]

bors r+

[bors[bot]]

Build succeeded

• continuous-integration/travis-ci/push

[brson]

Thanks @PaulGrandperrin ❤️