keynot 0.4.0

Added

• Dynamic shell completions: register once (one line, or a drop-in
  completion file for fish/bash) and keynot pl<TAB> completes from
  the live CLI -- subcommands, flags, and values.
• Press e during a show to open the deck in $VISUAL/$EDITOR at
  the line you are looking at (the highlighted block, or the top of
  the scrolled view); exiting the editor reloads from disk and
  resumes where you were. Knows the line-jump syntax for the vi/emacs
  family, VS Code, Sublime, and TextMate; falls back to vi
  (notepad on Windows).
• GFM tables render with rounded borders, bold headers, and per-column
  alignment; columns size to their content and word-wrap when the
  table is wider than the slide.
• GFM alerts (> [!NOTE] and friends) render a colored, labeled bar
  with an upright body; plain quotes stay italic.
• Footnotes: [^1] references become accent markers, with the notes
  collected at the end of their slide or column.
• Definition lists render bold terms with indented definitions.
• Heading attributes ({#id}) parse and no longer show as literal
  braces.
• Emoji shortcodes: :crab: and friends (GitHub's names) become real
  emoji in prose; unknown names and anything in code stay literal.
• keynot --help links to the crate page.
• Overflowing slides scroll: on a slide taller than the terminal,
  walking the line highlight (down/up) moves the view to follow the
  bar, with dim markers showing how many lines are hidden past each
  edge. Esc (or changing slides) returns to the top.
• keynot check reports the tallest slide and its height at a
  reference 80 columns; run in a terminal, it also says whether every
  slide fits that terminal's real size.