Add option for lang#zig layer

- ztagsbin: special the path of ztags

autoload/SpaceVim/layers/lang/zig.vim

@@ -6,6 +6,11 @@
 " License: GPLv3
 "=============================================================================
 
+if exists('s:ztagsbin')
+  finish
+endif
+let s:ztagsbin = 'ztags'
+
 function! SpaceVim#layers#lang#zig#plugins() abort
   let plugins = []
   call add(plugins, ['ziglang/zig.vim', { 'merged' : 0}])
@@ -20,3 +25,7 @@ endfunction
 function! s:language_specified_mappings() abort
   call SpaceVim#mapping#space#langSPC('nmap', ['l','r'], 'call SpaceVim#plugins#runner#open()', 'execute current file', 1)
 endfunction
+
+function! SpaceVim#layers#lang#zig#set_variable(opt) abort
+  let s:ztagsbin = get(a:opt, 'ztagsbin', s:ztagsbin) 
+endfunction

docs/cn/layers/lang/zig.md

@@ -10,6 +10,7 @@ lang: zh
 
 - [模块简介](#模块简介)
 - [启用模块](#启用模块)
+- [模块选项](#模块选项)
 - [快捷键](#快捷键)
   - [运行当前脚本](#运行当前脚本)
 
@@ -28,6 +29,10 @@ lang: zh
   name = "lang#zig"
 ```
 
+## 模块选项
+
+- `ztagsbin`:制定 ztags 命令的路径。
+
 ## 快捷键
 
 ### 运行当前脚本

docs/layers/lang/zig.md

@@ -9,6 +9,7 @@ description: "This layer is for zig development, provide code runner support for
 
 - [Description](#description)
 - [Install](#install)
+- [Options](#options)
 - [Key bindings](#key-bindings)
   - [Running current script](#running-current-script)
 
@@ -27,6 +28,10 @@ To use this configuration layer, update custom configuration file with:
   name = "lang#zig"
 ```
 
+## Options
+
+- `ztagsbin`: specific the path of ztags.
+
 ## Key bindings
 
 ### Running current script