brew: add alias for brew to avoid upgrading casks (#9280)

plugins/brew/README.md

@@ -15,10 +15,11 @@ plugins=(... brew)
 | `brewp`  | `brew pin`                                                    | Pin a specified formula so that it's not upgraded.                  |
 | `brews`  | `brew list -1`                                                | List installed formulae or the installed files for a given formula. |
 | `brewsp` | `brew list --pinned`                                          | List pinned formulae, or show the version of a given formula.       |
-| `bubo`   | `brew update && brew outdated`                                | Update Homebrew and all formulae, then list outdated formulae.      |
-| `bubc`   | `brew upgrade && brew cleanup`                                | Upgrade outdated formulae, then run cleanup.                        |
+| `bubo`   | `brew update && brew outdated`                                | Update Homebrew data, then list outdated formulae and casks.        |
+| `bubc`   | `brew upgrade && brew cleanup`                                | Upgrade outdated formulae and casks, then run cleanup.              |
 | `bubu`   | `bubo && bubc`                                                | Do the last two operations above.                                   |
-| `bcubo`  | `brew update && brew outdated --cask`                         | Update Homebrew and all formulae, then list outdated casks.        |
+| `buf`    | `brew upgrade --formula`                                      | Upgrade only formulas (not casks).                                  |
+| `bcubo`  | `brew update && brew outdated --cask`                         | Update Homebrew data, then list outdated casks.                     |
 | `bcubc`  | `brew cask reinstall $(brew outdated --cask) && brew cleanup` | Update outdated casks, then run cleanup.                            |
 
 ## Completion

plugins/brew/brew.plugin.zsh

@@ -4,5 +4,6 @@ alias brewsp='brew list --pinned'
 alias bubo='brew update && brew outdated'
 alias bubc='brew upgrade && brew cleanup'
 alias bubu='bubo && bubc'
+alias buf='brew upgrade --formula'
 alias bcubo='brew update && brew outdated --cask'
 alias bcubc='brew cask reinstall $(brew outdated --cask) && brew cleanup'