feat(brew): improve `brews` list layout (#10135)

This is an improvement (in my opinion) to the `brews` command that prints each leaf formula (in white), followed by its dependencies (in blue), on each line. Compared to the existing flat list of formulae, the new layout is both more compact and more informative, by differentiating leaves from dependencies at a glance.

Screenshot:
<img width="530" src="https://user-images.githubusercontent.com/1753319/130641713-b78535c9-e3f5-4dbb-80f8-22bc00e1129d.png">

plugins/brew/brew.plugin.zsh

 alias brewp='brew pin'
-alias brews='brew list -1'
 alias brewsp='brew list --pinned'
 alias bubo='brew update && brew outdated'
 alias bubc='brew upgrade && brew cleanup'
@@ -7,3 +6,16 @@ alias bubu='bubo && bubc'
 alias buf='brew upgrade --formula'
 alias bcubo='brew update && brew outdated --cask'
 alias bcubc='brew upgrade --cask && brew cleanup'
+
+function brews() {
+  local formulae="$(brew leaves | xargs brew deps --installed --for-each)"
+  local casks="$(brew list --cask)"
+
+  local blue="$(tput setaf 4)"
+  local bold="$(tput bold)"
+  local off="$(tput sgr0)"
+
+  echo "${blue}==>${off} ${bold}Formulae${off}"
+  echo "${formulae}" | sed "s/^\(.*\):\(.*\)$/\1${blue}\2${off}/"
+  echo "\n${blue}==>${off} ${bold}Casks${off}\n${casks}"
+}