Feature: VimwikiVar to list, get and set variables

Refaction:
- Add g:vimwiki_syntax_list to set syntaxlocal variables
- Delete: syntax/vimwiki_markdown.vim and friends
- Change: vimwiki_syntax_variables -> vimwiki_syntaxlocal_vars for consistency
- Include: some doc in design notes

autoload/vimwiki/base.vim

@@ -2163,7 +2163,7 @@ function! vimwiki#base#AddHeaderLevel(...) abort
   endif
   let lnum = line('.')
   let line = getline(lnum)
-  let rxHdr = vimwiki#vars#get_syntaxlocal('rxH')
+  let rxHdr = vimwiki#vars#get_syntaxlocal('header_symbol')
   if line =~# '^\s*$'
     return
   endif
@@ -2197,7 +2197,7 @@ function! vimwiki#base#RemoveHeaderLevel(...) abort
   endif
   let lnum = line('.')
   let line = getline(lnum)
-  let rxHdr = vimwiki#vars#get_syntaxlocal('rxH')
+  let rxHdr = vimwiki#vars#get_syntaxlocal('header_symbol')
   if line =~# '^\s*$'
     return
   endif
@@ -2269,7 +2269,7 @@ function! s:collect_headers() abort
       endif
       " Clause: markdown headers must start in the first column
       if vimwiki#vars#get_wikilocal('syntax') ==# 'markdown'
-            \ && stridx(line_content, vimwiki#vars#get_syntaxlocal('rxH')) > 0
+            \ && stridx(line_content, vimwiki#vars#get_syntaxlocal('header_symbol')) > 0
         continue
       endif
       " Get header level

autoload/vimwiki/html.vim

@@ -1296,8 +1296,9 @@ function! s:parse_line(line, state) abort
   " current line while not marking as processed in the scenario where some
   " text remains that needs to go through additional processing
   if !processed
-    let mc_start = vimwiki#vars#get_syntaxlocal('rxMultilineCommentStart')
-    let mc_end = vimwiki#vars#get_syntaxlocal('rxMultilineCommentEnd')
+    let mc_format = vimwiki#vars#get_syntaxlocal('multiline_comment_format')
+    let mc_start = mc_format.pre_mark
+    let mc_end = mc_format.post_mark
 
     " If either start or end is empty, we want to skip multiline handling
     if !empty(mc_start) && !empty(mc_end)
@@ -1396,7 +1397,7 @@ function! s:parse_line(line, state) abort
   endif
 
   if !processed
-    if line =~# vimwiki#vars#get_syntaxlocal('rxComment')
+    if line =~# vimwiki#vars#get_syntaxlocal('comment_regex')
       let processed = 1
     endif
   endif

autoload/vimwiki/u.vim

@@ -5,17 +5,22 @@
 
 " Echo: msg
 " :param: (1) <string> highlighting group
-" :param: (2) <string> echo suffix (ex: 'n', 'm'
+" :param: (2) <string> echo suffix (ex: 'n', 'm')
+" :param: (3) <string> message prefix, default Vimwiki
 function! vimwiki#u#echo(msg, ...) abort
   let hl_group = a:0 > 0 ? a:1 : ''
   let echo_suffix = a:0 > 1 ? a:2 : ''
+  let msg_prefix = a:0 > 2 ? a:3 : 'Vimwiki: '
   " Start highlighting
   if hl_group !=# ''
     exe 'echohl ' . hl_group
   endif
-  " Print
+
+  " Escape
   let msg = substitute(a:msg, "'", "''", 'g')
-  exe 'echo'.echo_suffix . " 'Vimwiki: " . msg . "'"
+  " Print
+  exe 'echo'.echo_suffix . " '" . msg_prefix . msg . "'"
+
   " Stop highlighting
   if hl_group !=# ''
     echohl None
@@ -267,7 +272,7 @@ endfunction
 " :param: syntax <string> to retrive, default to current
 function! vimwiki#u#get_syntax_dic(...) abort
   let syntax = a:0 ? a:1 : vimwiki#vars#get_wikilocal('syntax')
-  return g:vimwiki_syntax_variables[syntax]
+  return g:vimwiki_syntaxlocal_vars[syntax]
 endfunction