fix(deno): move guard check before aliases and remove deprecated commands

- Move the command existence check to the top of the plugin so aliases
  are not created when deno is not installed
- Remove  alias for  (deprecated and removed in Deno 2.0)
- Remove  alias for  (replaced by granular
  --unstable-* flags in Deno 2.0)
- Update README to reflect removed aliases and add usage instructions

plugins/deno/README.md

@@ -2,19 +2,23 @@
 
 This plugin sets up completion and aliases for [Deno](https://deno.land).
 
+To use it, add `deno` to the plugins array in your zshrc file:
+
+```zsh
+plugins=(... deno)
+```
+
 ## Aliases
 
-| Alias | Full command        |
-| ----- | ------------------- |
-| db    | deno bundle         |
-| dc    | deno compile        |
-| dca   | deno cache          |
-| dfmt  | deno fmt            |
-| dh    | deno help           |
-| dli   | deno lint           |
-| drn   | deno run            |
-| drA   | deno run -A         |
-| drw   | deno run --watch    |
-| dru   | deno run --unstable |
-| dts   | deno test           |
-| dup   | deno upgrade        |
+| Alias | Full command     |
+| ----- | ---------------- |
+| dc    | deno compile     |
+| dca   | deno cache       |
+| dfmt  | deno fmt         |
+| dh    | deno help        |
+| dli   | deno lint        |
+| drn   | deno run         |
+| drA   | deno run -A      |
+| drw   | deno run --watch |
+| dts   | deno test        |
+| dup   | deno upgrade     |

plugins/deno/deno.plugin.zsh

@@ -1,5 +1,9 @@
+# Return immediately if deno is not found
+if (( ! ${+commands[deno]} )); then
+  return
+fi
+
 # ALIASES
-alias db='deno bundle'
 alias dc='deno compile'
 alias dca='deno cache'
 alias dfmt='deno fmt'
@@ -8,15 +12,10 @@ alias dli='deno lint'
 alias drn='deno run'
 alias drA='deno run -A'
 alias drw='deno run --watch'
-alias dru='deno run --unstable'
 alias dts='deno test'
 alias dup='deno upgrade'
 
 # COMPLETION FUNCTION
-if (( ! $+commands[deno] )); then
-  return
-fi
-
 # If the completion file doesn't exist yet, we need to autoload it and
 # bind it to `deno`. Otherwise, compinit will have already done that.
 if [[ ! -f "$ZSH_CACHE_DIR/completions/_deno" ]]; then