Autocomplete only on email fields

autoload/ncm2_khard.vim

@@ -15,6 +15,7 @@ let g:ncm2_khard#source = extend(get(g:, 'ncm2_khard#source', {}), {
             \ 'mark': 'email',
             \ 'scope': ['mail'],
             \ 'complete_pattern': ['^To: ', '^Cc: ', '^Bcc: '],
+            \ 'complete_length': -1,
             \ 'on_complete': 'ncm2_khard#on_complete',
             \ 'on_warmup': 'ncm2_khard#on_warmup',
             \ }, 'keep')