fix(tutor): set a value for ":syntax iskeyword" (#27833)

Problem: "NOTE"s, inline Vim script code, and links ending in digits may not be
highlighted correctly within the :Tutor.

Solution: set an explicit value for ":syntax iskeyword" that includes digits. Do
it after ":syntax include"s, so the included syntax/sh.vim doesn't mess with the
value.

Increase screen test width so all text within the conclusion section is visible.

Co-authored-by: Sean Dewar <6256228+seandewar@users.noreply.github.com>

runtime/syntax/tutor.vim

@@ -8,6 +8,8 @@ syn include @TUTORSHELL syntax/sh.vim
 unlet b:current_syntax
 syn include @VIMNORMAL syntax/vimnormal.vim
 
+syn iskeyword @,-,_,48-57
+
 syn match tutorLink /\[.\{-}\](.\{-})/ contains=tutorInlineNormal
 syn match tutorLinkBands /\[\|\]\|(\|)/ contained containedin=tutorLink,tutorLinkAnchor conceal
 syn match tutorLinkAnchor /(.\{-})/ contained containedin=tutorLink conceal

test/functional/plugin/tutor_spec.lua

@@ -12,7 +12,7 @@ describe(':Tutor', function()
     clear({ args = { '--clean' } })
     command('set cmdheight=0')
     command('Tutor')
-    screen = Screen.new(80, 30)
+    screen = Screen.new(81, 30)
     screen:set_default_attr_ids({
       [0] = { foreground = Screen.colors.DarkBlue, background = Screen.colors.Gray },
       [1] = { bold = true },
@@ -20,6 +20,7 @@ describe(':Tutor', function()
       [3] = { foreground = Screen.colors.SlateBlue },
       [4] = { bold = true, foreground = Screen.colors.Brown },
       [5] = { bold = true, foreground = Screen.colors.Magenta1 },
+      [6] = { italic = true },
     })
     screen:attach()
   end)
@@ -94,4 +95,42 @@ describe(':Tutor', function()
     feed(':700<CR>zt')
     screen:expect(expected)
   end)
+
+  it('applies hyperlink highlighting', function()
+    local expected = [[
+      {0:  }^                                                                               |
+      {0:  }{3:#}{5: CONCLUSION}                                                                   |
+      {0:  }                                                                               |
+      {0:  }This was intended to give a brief overview of the Neovim editor, just enough to|
+      {0:  }allow you to use it fairly easily. It is far from complete as Neovim has       |
+      {0:  }many many more commands. Consult the help often.                               |
+      {0:  }There are also countless great tutorials and videos to be found online.        |
+      {0:  }Here's a bunch of them:                                                        |
+      {0:  }                                                                               |
+      {0:  }- {6:Learn Vim Progressively}:                                                     |
+      {0:  }  {2:https://yannesposito.com/Scratch/en/blog/Learn-Vim-Progressively/}            |
+      {0:  }- {6:Learning Vim in 2014}:                                                        |
+      {0:  }  {2:https://benmccormick.org/learning-vim-in-2014/}                               |
+      {0:  }- {6:Vimcasts}:                                                                    |
+      {0:  }  {2:http://vimcasts.org/}                                                         |
+      {0:  }- {6:Vim Video-Tutorials by Derek Wyatt}:                                          |
+      {0:  }  {2:http://derekwyatt.org/vim/tutorials/}                                         |
+      {0:  }- {6:Learn Vimscript the Hard Way}:                                                |
+      {0:  }  {2:https://learnvimscriptthehardway.stevelosh.com/}                              |
+      {0:  }- {6:7 Habits of Effective Text Editing}:                                          |
+      {0:  }  {2:https://www.moolenaar.net/habits.html}                                        |
+      {0:  }- {6:vim-galore}:                                                                  |
+      {0:  }  {2:https://github.com/mhinz/vim-galore}                                          |
+      {0:  }                                                                               |
+      {0:  }If you prefer a book, {6:Practical Vim} by Drew Neil is recommended often          |
+      {0:  }(the sequel, {6:Modern Vim}, includes material specific to Neovim).                |
+      {0:  }                                                                               |
+      {0:  }This tutorial was written by Michael C. Pierce and Robert K. Ware, Colorado    |
+      {0:  }School of Mines using ideas supplied by Charles Smith, Colorado State          |
+      {0:  }University. E-mail: {2:bware@mines.colorado.edu}.                                  |
+    ]]
+
+    feed(':960<CR>zt')
+    screen:expect(expected)
+  end)
 end)