gopls/doc/release/v0.16.0.md: augment notes for "view pkg doc"

Change-Id: Ieaef6c74b7fe1f7d736c1fb23c13c7569193ff3a
Reviewed-on: https://go-review.googlesource.com/c/tools/+/575376
Reviewed-by: Robert Findley <[email protected]>
Auto-Submit: Alan Donovan <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>

Author: adonovan

gopls/doc/release/v0.16.0.md

@@ -16,13 +16,31 @@ read the documentation for locally edited packages, even ones that
 have not yet been saved. Reload the page after an edit to see updated
 documentation.
 
-TODO: demo of VS Code `Source action > View package documentation`.
+TODO: demo in VS Code.
 
 Clicking on the source-code link associated with a declaration will
 cause your editor to navigate to the declaration.
 
 TODO: demo of source linking.
-TODO: appeal to VS Code users to upvote https://github.com/microsoft/vscode/issues/208093?
+
+Editor support:
+
+- VS Code: use the `Source action > View package documentation` menu item.
+  Note: source links navigate the editor but don't yet raise the window yet.
+  Please upvote https://github.com/microsoft/vscode/issues/208093 and
+  https://github.com/microsoft/vscode/issues/207634 (temporarily closed).
+
+- Emacs: requires eglot v1.17. You may find this `go-doc` function a
+  useful shortcut:
+
+```lisp
+(eglot--code-action eglot-code-action-doc "source.doc")
+
+(defalias 'go-doc #'eglot-code-action-doc
+  "View documentation for the current Go package.")
+```
+
+- TODO: test in vim, neovim, sublime, helix.
 
 ### `unusedwrite` analyzer