Allow to exclude by buffer types (#235)

* Filter by buftype

* Add docs

* Typo

after/plugin/indentLine.vim

@@ -19,6 +19,7 @@ let g:indentLine_enabled = get(g:, 'indentLine_enabled', 1)
 let g:indentLine_fileType = get(g:, 'indentLine_fileType', [])
 let g:indentLine_fileTypeExclude = get(g:, 'indentLine_fileTypeExclude', [])
 let g:indentLine_bufNameExclude = get(g:, 'indentLine_bufNameExclude', [])
+let g:indentLine_bufTypeExclude = get(g:, 'indentLine_bufTypeExclude', [])
 let g:indentLine_showFirstIndentLevel = get(g:, 'indentLine_showFirstIndentLevel', 0)
 let g:indentLine_maxLines = get(g:, 'indentLine_maxLines', 3000)
 let g:indentLine_setColors = get(g:, 'indentLine_setColors', 1)
@@ -210,6 +211,10 @@ function! s:Filter()
         return 0
     endif
 
+    if index(g:indentLine_bufTypeExclude, &buftype) != -1
+        return 0
+    endif
+
     if len(g:indentLine_fileType) != 0 && index(g:indentLine_fileType, &filetype) == -1
         return 0
     endif

doc/indentLine.txt

@@ -99,7 +99,14 @@ g:indentLine_fileTypeExclude                    *g:indentLine_fileTypeExclude*
                 When opening these types of files, the plugin is disabled by
                 default.
                 e.g. let g:indentLine_fileTypeExclude = ['text', 'sh']
-                Default value is [] which means no file types is excluded.
+                Default value is [] which means no file types are excluded.
+
+g:indentLine_bufTypeExclude                    *g:indentLine_bufTypeExclude*
+                This variable specify a list of buffer types.
+                When opening these types of buffers, the plugin is disabled
+                by default.
+                e.g. let g:indentLine_bufTypeExclude = ['help', 'terminal']
+                Default value is [] which means no buffer type is excluded.
 
 g:indentLine_bufNameExclude                     *g:indentLine_bufNameExclude*
                 This variable specify a list of buffer names, which can be