net/http: Typo in Documentation

[benpbrown]

What did you do? Read the documentation
What did you expect to see? The word "directory"
What did you see instead? The word "direcory"

go/src/net/http/fs.go

Line 454 in b04f3b0

// If the provided file or direcory name is a relative path, it is

https://golang.org/pkg/net/http/#ServeFile