cmd/edit: stop double warning

When you don't have EDITOR or HOMEBREW_EDITOR
configured `brew edit` printed a double warning.

This silences the first of those.

Library/Homebrew/dev-cmd/edit.rb

@@ -45,7 +45,7 @@ module Homebrew
     paths = if args.named.empty?
       # Sublime requires opting into the project editing path,
       # as opposed to VS Code which will infer from the .vscode path
-      if which_editor == "subl"
+      if which_editor(silent: true) == "subl"
         ["--project", "#{HOMEBREW_REPOSITORY}/.sublime/homebrew.sublime-project"]
       else
         # If no formulae are listed, open the project root in an editor.

Library/Homebrew/utils.rb

@@ -361,7 +361,7 @@ module Kernel
     end.compact.uniq
   end
 
-  def which_editor
+  def which_editor(silent: false)
     editor = Homebrew::EnvConfig.editor
     return editor if editor
 
@@ -371,11 +371,13 @@ module Kernel
     end
     editor ||= "vim"
 
-    opoo <<~EOS
-      Using #{editor} because no editor was set in the environment.
-      This may change in the future, so we recommend setting EDITOR,
-      or HOMEBREW_EDITOR to your preferred text editor.
-    EOS
+    unless silent
+      opoo <<~EOS
+        Using #{editor} because no editor was set in the environment.
+        This may change in the future, so we recommend setting EDITOR,
+        or HOMEBREW_EDITOR to your preferred text editor.
+      EOS
+    end
 
     editor
   end