docs: fix typo (ipfs#3189)

execllent -> excellent

Author: jaller94

examples/browser-readablestream/README.md

@@ -1,6 +1,6 @@
 # Streaming video from IPFS using ReadableStreams
 
-We can use the execllent [`videostream`](https://www.npmjs.com/package/videostream) to stream video from IPFS to the browser.  All we need to do is return a [`ReadableStream`](https://developer.mozilla.org/en-US/docs/Web/API/ReadableStream)-like object that contains the requested byte ranges.
+We can use the excellent [`videostream`](https://www.npmjs.com/package/videostream) to stream video from IPFS to the browser.  All we need to do is return a [`ReadableStream`](https://developer.mozilla.org/en-US/docs/Web/API/ReadableStream)-like object that contains the requested byte ranges.
 
 Take a look at [`index.js`](./index.js) to see a working example.