Add command and map to jump to the next unfinished task.

Introduce the command `VimwikiNextTask` and the mapping `gnt` to jump to
the next unfinished task.

autoload/vimwiki/base.vim

@@ -1156,6 +1156,11 @@ function! vimwiki#base#update_listing_in_buffer(strings, start_header,
   call winrestview(winview_save)
 endfunction
 
+function! vimwiki#base#find_next_task()
+  let taskRegex = vimwiki#vars#get_syntaxlocal('rxListItemWithoutCB')
+    \ . '\+\(\[ \]\s\+\)\zs'
+  call vimwiki#base#search_word(taskRegex, '')
+endfunction
 
 function! vimwiki#base#find_next_link()
   call vimwiki#base#search_word(vimwiki#vars#get_syntaxlocal('rxAnyLink'), '')

doc/vimwiki.txt

@@ -317,6 +317,12 @@ NORMAL MODE                                           *vimwiki-local-mappings*
                         Maps to |:VimwikiPrevLink|.
                         To remap: >
                         :nmap <Leader>wp <Plug>VimwikiPrevLink
+<
+gnt			*vimwiki_gnt*
+			Find next unfinished task in the current page.
+			Maps to |:VimwikiNextTask|
+			To remap: >
+			:nmap <Leader>nt <Plug>VimwikiNextTask
 <
                         *vimwiki_<Leader>wd*
 <Leader>wd              Delete wiki page you are in.
@@ -723,6 +729,9 @@ Vimwiki file.
 *:VimwikiRenameLink*
     Rename the wiki page you are in.
 
+*:VimwikiNextTask*
+    Jump to the next unfinished task in the current wiki page.
+
 *:Vimwiki2HTML*
     Convert current wiki page to HTML using Vimwiki's own converter or a
     user-supplied script (see |vimwiki-option-custom_wiki2html|).

ftplugin/vimwiki.vim

@@ -253,6 +253,7 @@ command! -buffer VimwikiAll2HTML
 
 command! -buffer VimwikiTOC call vimwiki#base#table_of_contents(1)
 
+command! -buffer VimwikiNextTask call vimwiki#base#find_next_task()
 command! -buffer VimwikiNextLink call vimwiki#base#find_next_link()
 command! -buffer VimwikiPrevLink call vimwiki#base#find_prev_link()
 command! -buffer VimwikiDeleteLink call vimwiki#base#delete_link()
@@ -381,6 +382,11 @@ endif
 vnoremap <silent><script><buffer>
       \ <Plug>VimwikiNormalizeLinkVisualCR :<C-U>VimwikiNormalizeLink 1<CR>
 
+if !hasmapto('<Plug>VimwikiNextTask')
+  nmap <silent><buffer> gnt <Plug>VimwikiNextTask
+endif
+nnoremap <silent><script><buffer> <Plug>VimwikiNextTask :VimwikiNextTask<CR>
+
 if !hasmapto('<Plug>VimwikiTabnewLink')
   nmap <silent><buffer> <D-CR> <Plug>VimwikiTabnewLink
   nmap <silent><buffer> <C-S-CR> <Plug>VimwikiTabnewLink