For some strange reason, Make wouldn't know how to get tutorial.ms.
Replacing it with an equivalent `%` works flawlessly, though.

* The old heuristics - scroll if dot changes after key press -
  turned out to be too simplistic.
  They broke the clang-format macro (M#cf), which left the view at the
  top of the document since the entire document is temporarily erased.
  Other simplified examples of this bug would be:
  @^Um{[: HECcat$ ]:} Mm
  Or even: @^Um{[: H@X.aG.a ]:} Mm
* Actually, the heuristics could be tricked even without deleting any
  significant amount of text from the buffer.
  The following test case replaces the previous character with a linefeed
  in a single key press:
  @^Um{-DI^J$} Mm
  If executed on the last visible line, dot wouldn't be scrolled into the view
  since it did not change.
* At the same time, we'd like to keep the existing mouse scroll behavior from
  fnkeys.tes, which is allowed to scroll dot outside of the visible area.
  Therefore, dot is scrolled into view always, except after mouse events.
  You may have to call SCI_SCROLLCARET manually in the ^KMOUSE macro,
  which is arguably not always straight forward.
* Some macros like M#cf may still leave the vertical scrolling position
  in unexpected positions. This could either be fixed by eradicating all
  remaining automatic scrolling from Scintilla or by explicitly restoring
  the vertical position from the macro (FIXME).
* This was broken since the introduction of mouse support,
  so it wasn't in v2.3.0.

* `--enable-html-manual` renamed to `--enable-html-docs`.
* It's also uploaded to the website and linked to in README.

Fixes `make distcheck` and CI builds.

This fixes building of the new tutorial.woman on Ubuntu.

* This is rendered with ms, so we now need the entire groff on Debian.
  This is not a big deal as it just adds a few kilobytes of build-time dependencies.
  Most platforms do not allow installation of some "groff-base" package anyway
  and always draw in the entire package.
* sciteco.tmac has been extended to disable page breaks on ms.
* The tutorial is installed like any other woman page and can be invoked
  interactively with ?tutorial$.
* It is optimized to be still usable on a plain 80x24 terminal.

* It makes little sense to e.g. rub out until `I` in `@I/foo/`, but
  leave the `@` modifier.
  Modifiers have to be considered part of the command,
  even though the state machine is not currently modelled like that.

* They swap the default order of skipping characters.
  For positive arguments: first non-word chars, then word chars.
* This is especially useful after executing the non-at-modified versions.
  For instance, at the beginning of a word, `@W` jumps to its end.
  `@V` would delete the remainder of the word.
* Since they have to evaluate the at-modifier, which has syntactic
  significance, the command implementations can no longer use
  transition tables, so they are in the switch-statements instead.