bundler: format aliases table and clean up README (#9300)

Co-authored-by: Marc Cornellà <marc.cornella@live.com>

plugins/bundler/README.md

 # Bundler
 
-- Adds completion for basic bundler commands
-
-- Adds short aliases for common bundler commands
-  - `ba` aliased to `bundle add`
-  - `be` aliased to `bundle exec`.
-    It also supports aliases (if `rs` is `rails server`, `be rs` will bundle-exec `rails server`).
-  - `bl` aliased to `bundle list`
-  - `bp` aliased to `bundle package`
-  - `bo` aliased to `bundle open`
-  - `bout` aliased to `bundle outdated`
-  - `bu` aliased to `bundle update`
-  - `bi` aliased to `bundle install --jobs=<cpu core count>` (only for bundler `>= 1.4.0`)
-  - `bcn` aliased to `bundle clean`
-  - `bck` aliased to `bundle check`
-
-- Adds a wrapper for common gems:
-  - Looks for a binstub under `./bin/` and executes it (if present)
-  - Calls `bundle exec <gem executable>` otherwise
+This plugin adds completion for basic bundler commands, as well as aliases and helper functions for
+an easier experience with bundler.
+
+To use it, add `bundler` to the plugins array in your zshrc file:
+
+```zsh
+plugins=(... bundler)
+```
+
+## Aliases
+
+| Alias  | Command                              | Description                                                                              |
+|--------|--------------------------------------|------------------------------------------------------------------------------------------|
+| `ba`   | `bundle add`                         | Add gem to the Gemfile and run bundle install                                            |
+| `bck`  | `bundle check`                       | Verifies if dependencies are satisfied by installed gems                                 |
+| `bcn`  | `bundle clean`                       | Cleans up unused gems in your bundler directory                                          |
+| `be`   | `bundle exec`                        | Execute a command in the context of the bundle                                           |
+| `bi`   | `bundle install --jobs=<core_count>` | Install the dependencies specified in your Gemfile (using all cores in bundler >= 1.4.0) |
+| `bl`   | `bundle list`                        | List all the gems in the bundle                                                          |
+| `bo`   | `bundle open`                        | Opens the source directory for a gem in your bundle                                      |
+| `bout` | `bundle outdated`                    | List installed gems with newer versions available                                        |
+| `bp`   | `bundle package`                     | Package your needed .gem files into your application                                     |
+| `bu`   | `bundle update`                      | Update your gems to the latest available versions                                        |
+
+## Gem wrapper
+
+The plugin adds a wrapper for common gems, which:
+
+- Looks for a binstub under `./bin/` and executes it if present.
+- Calls `bundle exec <gem>` otherwise.
 
 Common gems wrapped by default (by name of the executable):
+
 `annotate`, `cap`, `capify`, `cucumber`, `foodcritic`, `guard`, `hanami`, `irb`, `jekyll`, `kitchen`, `knife`, `middleman`, `nanoc`, `pry`, `puma`, `rackup`, `rainbows`, `rake`, `rspec`, `rubocop`, `shotgun`, `sidekiq`, `spec`, `spork`, `spring`, `strainer`, `tailor`, `taps`, `thin`, `thor`, `unicorn` and `unicorn_rails`.
 
-## Configuration
+### Settings
 
-Please use the exact name of the executable and not the gem name.
+You can add or remove gems from the list of wrapped commands.
+Please **use the exact name of the executable** and not the gem name.
 
-### Add additional gems to be wrapped
+#### Include gems to be wrapped (`BUNDLED_COMMANDS`)
 
-Add this before the plugin-list in your `.zshrc`:
+Add this before the plugin list in your `.zshrc`:
 
 ```sh
 BUNDLED_COMMANDS=(rubocop)
@@ -37,10 +51,9 @@ plugins=(... bundler ...)
 
 This will add the wrapper for the `rubocop` gem (i.e. the executable).
 
+#### Exclude gems from being wrapped (`UNBUNDLED_COMMANDS`)
 
-### Exclude gems from being wrapped
-
-Add this before the plugin-list in your `.zshrc`:
+Add this before the plugin list in your `.zshrc`:
 
 ```sh
 UNBUNDLED_COMMANDS=(foreman spin)
@@ -49,13 +62,13 @@ plugins=(... bundler ...)
 
 This will exclude the `foreman` and `spin` gems (i.e. their executable) from being wrapped.
 
-## Excluded gems
+### Excluded gems
 
-These gems should not be called with `bundle exec`. Please see [issue #2923](https://github.com/ohmyzsh/ohmyzsh/pull/2923) on GitHub for clarification.
+These gems should not be called with `bundle exec`. Please see [issue #2923](https://github.com/ohmyzsh/ohmyzsh/pull/2923) on GitHub for clarification:
 
-`berks`
-`foreman`
-`mailcatcher`
-`rails`
-`ruby`
-`spin`
+- `berks`
+- `foreman`
+- `mailcatcher`
+- `rails`
+- `ruby`
+- `spin`