doc: update editors.html for Go 1.16

Rerank editor plugins based on popularity (Go 2019 survey), and remove
Atom, as it is no longer popular.

Change-Id: I06d39b67eec24a920439b9ea1198b6e2a939874e
Reviewed-on: https://go-review.googlesource.com/c/go/+/283073
Trust: Rebecca Stambler <rstambler@golang.org>
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>

doc/editors.html

@@ -19,13 +19,11 @@ <h2 id="options">Options</h2>
 </p>
 
 <ul>
-<li><a href="https://github.com/fatih/vim-go">vim</a>: vim-go plugin provides Go programming language support</li>
 <li><a href="https://marketplace.visualstudio.com/items?itemName=golang.go">Visual Studio Code</a>:
 Go extension provides support for the Go programming language</li>
 <li><a href="https://www.jetbrains.com/go">GoLand</a>: GoLand is distributed either as a standalone IDE
 or as a plugin for IntelliJ IDEA Ultimate</li>
-<li><a href="https://atom.io/packages/go-plus">Atom</a>: Go-Plus is an Atom package that provides enhanced Go support</li>
-</ul>
+<li><a href="https://github.com/fatih/vim-go">vim</a>: vim-go plugin provides Go programming language support</li>
 
 <p>
 Note that these are only a few top solutions; a more comprehensive