patch 9.1.1404: wrong link to Chapter 2 in new-tutor

Problem:  wrong link to Chapter 2 in vim-01-beginner.tutor
Solution: Fix the link to Chapter 2, add test for links in tutor files
          (Phạm Bình An)

In order to write the test, I expose the function `s:GlobTutorials` as
`tutor#GlobTutorials` and make it also accept a `locale` argument.

closes: #17356

Signed-off-by: Phạm Bình An <111893501+brianhuster@users.noreply.github.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/autoload/tutor.vim b/runtime/autoload/tutor.vim
index 6ab7960..b21e20f 100644
--- a/runtime/autoload/tutor.vim
+++ b/runtime/autoload/tutor.vim
@@ -157,12 +157,14 @@
     return retval
 endfunction
 
-function! s:GlobTutorials(name)
+" returns a list of all tutor files matching the given name
+function! tutor#GlobTutorials(name, locale)
+    let locale = a:locale
     " search for tutorials:
     " 1. non-localized
     let l:tutors = s:GlobPath(&rtp, 'tutor/'.a:name.'.tutor')
     " 2. localized for current locale
-    let l:locale_tutors = s:GlobPath(&rtp, 'tutor/'.s:Locale()[0].'/'.a:name.'.tutor')
+    let l:locale_tutors = s:GlobPath(&rtp, 'tutor/'.locale.'/'.a:name.'.tutor')
     " 3. fallback to 'en'
     if len(l:locale_tutors) == 0
         let l:locale_tutors = s:GlobPath(&rtp, 'tutor/en/'.a:name.'.tutor')
@@ -187,7 +189,7 @@
         let l:tutor_name = fnamemodify(l:tutor_name, ':r')
     endif
 
-    let l:tutors = s:GlobTutorials(l:tutor_name)
+    let l:tutors = tutor#GlobTutorials(l:tutor_name, s:Locale()[0])
 
     if len(l:tutors) == 0
         echom "No tutorial with that name found"
@@ -214,7 +216,7 @@
 endfunction
 
 function! tutor#TutorCmdComplete(lead,line,pos)
-    let l:tutors = s:GlobTutorials('*')
+    let l:tutors = tutor#GlobTutorials('*', s:Locale()[0])
     let l:names = uniq(sort(map(l:tutors, 'fnamemodify(v:val, ":t:r")'), 's:Sort'))
     return join(l:names, "\n")
 endfunction
diff --git a/runtime/tutor/en/vim-01-beginner.tutor b/runtime/tutor/en/vim-01-beginner.tutor
index 86efa78..8af5d46 100644
--- a/runtime/tutor/en/vim-01-beginner.tutor
+++ b/runtime/tutor/en/vim-01-beginner.tutor
@@ -970,7 +970,7 @@
 # CONCLUSION
 
 This concludes Chapter 1 of the Vim Tutor.  Consider continuing with
-[Chapter 2](@tutor:tutor:vim-02-beginner).
+[Chapter 2](@tutor:vim-02-beginner).
 
 This was intended to give a brief overview of the Vim editor, just enough to
 allow you to use the editor fairly easily. It is far from complete as Vim has