Show list of dependencies prior to installing them

Closes Homebrew/homebrew#22205.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>

Library/Homebrew/formula_installer.rb

@@ -207,6 +207,7 @@ class FormulaInstaller
   end
 
   def install_dependencies
+    oh1 "Installing dependencies for #{f}: #{Tty.green}#{effective_deps.join(", ")}#{Tty.reset}" if not effective_deps.empty?
     effective_deps.each do |dep|
       if dep.requested?
        install_dependency(dep)