[add#keymap] more customization

Added more customization for keymap extension

autoload/airline/extensions/keymap.vim

@@ -9,7 +9,18 @@ endif
 
 function! airline#extensions#keymap#status()
   if (get(g:, 'airline#extensions#keymap#enabled', 1) && has('keymap'))
-    return printf('%s', (!empty(&keymap) && &iminsert ? (g:airline_symbols.keymap . ' '. &keymap) : ''))
+    let short_codes = get(g:, 'airline#extensions#keymap#short_codes')
+    let label = get(g:, 'airline#extensions#keymap#label', g:airline_symbols.keymap)
+    let default = get(g:, 'airline#extensions#keymap#default', '')
+    if (label !=# '')
+      let label .= ' '
+    endif
+    let keymap = &keymap
+    if has_key(short_codes, keymap)
+      let keymap = short_codes[keymap]
+    endif
+    return printf('%s', (!empty(keymap) && &iminsert ? (label . keymap) :
+          \ (!empty(default) ? label . default : default)))
   else
     return ''
   endif

doc/airline.txt

@@ -826,6 +826,15 @@ This extension displays the current 'keymap' in use.
 * enable/disable vim-keymap extension >
   let g:airline#extensions#keymap#enabled = 1
 
+* set label for a keymap (default is from g:airline_symbols.keymap) >
+  let g:airline#extensions#keymap#label = 'Layout:'
+
+* set name for default lauout (empty to disable it completely) >
+  let g:airline#extensions#keymap#default = ''
+
+* set short codes for layout names >
+  let g:airline#extensions#keymap#short_codes = {'russian-jcukenwin': 'ru'}
+
 -------------------------------------                *airline-languageclient*
 LanguageClient <https://github.com/autozimu/LanguageClient-neovim>
 (despite its name, it can be used for Vim and Neovim).