[add] support battery.vim

autoload/airline/extensions/battery.vim

@@ -0,0 +1,20 @@
+" MIT License. Copyright (c) 2014-2020 Mathias Andersson et al.
+" Plugin: https://github.com/lambdalisue/battery.vim
+" vim: et ts=2 sts=2 sw=2
+
+scriptencoding utf-8
+
+if !exists('g:loaded_battery')
+  finish
+endif
+
+function! airline#extensions#battery#status(...) abort
+  if !exists('g:battery#update_statusline') 
+    let g:battery#update_statusline = 1
+  endif
+  let w:airline_section_z = '%{battery#component()}'
+endfunction
+
+function! airline#extensions#battery#init(ext) abort
+  call a:ext.add_statusline_func('airline#extensions#battery#status')
+endfunction