README.md: link to pkg.go.dev for golang.org/x/sys package (#441)

Also add a link to the syscall package and remove some trailing
whitespaces.

README.md

@@ -2,9 +2,7 @@
 
 [![Go Reference](https://pkg.go.dev/badge/github.com/fsnotify/fsnotify.svg)](https://pkg.go.dev/github.com/fsnotify/fsnotify) [![Go Report Card](https://goreportcard.com/badge/github.com/fsnotify/fsnotify)](https://goreportcard.com/report/github.com/fsnotify/fsnotify) [![Maintainers Wanted](https://img.shields.io/badge/maintainers-wanted-red.svg)](https://github.com/fsnotify/fsnotify/issues/413)
 
-
-
-fsnotify utilizes [golang.org/x/sys](https://godoc.org/golang.org/x/sys) rather than `syscall` from the standard library. 
+fsnotify utilizes [`golang.org/x/sys`](https://pkg.go.dev/golang.org/x/sys) rather than [`syscall`](https://pkg.go.dev/syscall) from the standard library.
 
 Cross platform: Windows, Linux, BSD and macOS.
 
@@ -25,7 +23,7 @@ Please see [the documentation](https://pkg.go.dev/github.com/fsnotify/fsnotify)
 
 ## API stability
 
-fsnotify is a fork of [howeyc/fsnotify](https://github.com/howeyc/fsnotify) with a new API as of v1.0. The API is based on [this design document](http://goo.gl/MrYxyA). 
+fsnotify is a fork of [howeyc/fsnotify](https://github.com/howeyc/fsnotify) with a new API as of v1.0. The API is based on [this design document](http://goo.gl/MrYxyA).
 
 All [releases](https://github.com/fsnotify/fsnotify/releases) are tagged based on [Semantic Versioning](http://semver.org/).