Tutorial of wee_alloc contains a typo

[pione30]

🐛 Bug description

The documantation 5.2.2.4 wee_alloc contains a typo:

wee_alloc trades off size for speed. It has a tiny code-size footprint, but it is is not competitive in terms of performance with the default global allocator, for example.

🤔 Expected Behavior

The duplicated "is" is removed.

👟 Steps to reproduce

Navigate to https://rustwasm.github.io/docs/wasm-pack/tutorials/npm-browser-packages/template-deep-dive/wee_alloc.html#what-is-wee_alloc

🌍 Your environment

Include the relevant details of your environment.
wasm-pack version: N/A
rustc version: N/A