feat(help): standardize colored --help output across functions

Add the established c_head/c_cmd/c_flag/c_dim/c_arg color scheme to
--help (or usage-on-error) output in play-media and 13 other functions
that lacked it or used an ad hoc scheme: bkg, detach, replay, p, y,
spark, wake-lock, open-url, repo-open, dng2avif, dockup, fish-deps
(__fish_deps_help), and scrub.

Also tweak the standard itself:
- c_cmd now uses plain `set_color --bold` instead of `--bold white`,
  so the command name adapts to the terminal's foreground instead of
  forcing white text that washes out on light-background themes.
  Applied across all functions already using the pattern.
- jobrunner's reset variable renamed from c_rst to c_reset to match
  the naming used everywhere else.

functions/p.fish

@@ -28,16 +28,20 @@
 function p --description 'Put from clipboard'
     # Check for help flag
     if contains -- -h $argv; or contains -- --help $argv
-        echo "Usage: p [OPTIONS]"
+        set -l c_head (set_color --bold cyan)
+        set -l c_cmd (set_color --bold)
+        set -l c_flag (set_color yellow)
+        set -l c_dim (set_color brblack)
+        set -l c_reset (set_color normal)
+        echo "$c_head""Usage:$c_reset $c_cmd""p$c_reset $c_flag""[OPTIONS]$c_reset"
         echo ""
-        echo "Description:"
         echo "  Pastes content from the system clipboard to stdout."
         echo ""
-        echo "Examples:"
-        echo "  p                Print clipboard content"
-        echo "  p > file.txt     Save clipboard to a file"
-        echo "  p | grep 'foo'   Pipe clipboard content to another command"
-        echo "  cat (p)          Use clipboard content as a filename for cat"
+        echo "$c_head""Examples:$c_reset"
+        echo "  $c_cmd""p$c_reset                "$c_dim"Print clipboard content"$c_reset
+        echo "  $c_cmd""p$c_reset > file.txt     "$c_dim"Save clipboard to a file"$c_reset
+        echo "  $c_cmd""p$c_reset | grep 'foo'   "$c_dim"Pipe clipboard content to another command"$c_reset
+        echo "  cat ($c_cmd""p$c_reset)          "$c_dim"Use clipboard content as a filename for cat"$c_reset
         return 0
     end