docs: fix typo on README

Author: daviddias

README.md

@@ -164,10 +164,10 @@ $ ipfs config --json API.HTTPHeaders.Access-Control-Allow-Methods "[\"PUT\", \"P
   - [`ipfs.files.add(data, [options], [callback])`](https://github.com/ipfs/interface-ipfs-core/tree/master/SPEC/FILES.md#add). Alias to `ipfs.add`.
   - [`ipfs.files.addReadableStream([options])`](https://github.com/ipfs/interface-ipfs-core/tree/master/SPEC/FILES.md#addreadablestream)
   - [`ipfs.files.addPullStream([options])`](https://github.com/ipfs/interface-ipfs-core/tree/master/SPEC/FILES.md#addpullstream)
-  - [`ipfs.files.cat(ipfsPath, [callback])`](https://github.com/ipfs/interface-ipfs-core/tree/master/SPEC/FILES.md#cat). Alias to `ipfs.cat`.
+  - [`ipfs.files.cat(ipfsPath, [options], [callback])`](https://github.com/ipfs/interface-ipfs-core/tree/master/SPEC/FILES.md#cat). Alias to `ipfs.cat`.
   - [`ipfs.files.catReadableStream(ipfsPath, [options])`](https://github.com/ipfs/interface-ipfs-core/tree/master/SPEC/FILES.md#catreadablestream)
   - [`ipfs.files.catPullStream(ipfsPath, [options])`](https://github.com/ipfs/interface-ipfs-core/tree/master/SPEC/FILES.md#catpullstream)  
-  - [`ipfs.files.get(ipfsPath, [callback])`](https://github.com/ipfs/interface-ipfs-core/tree/master/SPEC/FILES.md#get). Alias to `ipfs.get`.
+  - [`ipfs.files.get(ipfsPath, [options], [callback])`](https://github.com/ipfs/interface-ipfs-core/tree/master/SPEC/FILES.md#get). Alias to `ipfs.get`.
   - [`ipfs.files.getReadableStream(ipfsPath, [options])`](https://github.com/ipfs/interface-ipfs-core/tree/master/SPEC/FILES.md#getreadablestream)
   - [`ipfs.files.getPullStream(ipfsPath, [options])`](https://github.com/ipfs/interface-ipfs-core/tree/master/SPEC/FILES.md#getpullstream)  
   - `ipfs.ls`