fix(mv): bring header and completions up to repo conventions

The EXIT STATUS block used a single space before the ">0" row's
description, which falls below the doc pipeline's 2-space column
threshold and silently degrades the rendered site page from a table
(like rm's) to a plain indented block. Pad it to match. Also strip
trailing whitespace from two DESCRIPTION lines and add --wraps='mv'
so fish inherits real mv's completions, matching the bash/top wrapper
convention.

functions/mv.fish

@@ -25,7 +25,7 @@
 #
 # EXAMPLE
 #   mv ~/.config/btop/themes/themes ~/.config/btop/themes
-function mv --description 'Move files with auto-collapse for nested directories'
+function mv --wraps='mv' --description 'Move files with auto-collapse for nested directories'
     # Opinionated guard (C1): fall back to bare command mv when disabled.
     if not __fish_config_op_enabled __fish_config_op_aliases
         command mv $argv