docs: document update_on_bufenter option

README.md

@@ -193,6 +193,8 @@ let g:signify_skip_filename = { '/home/user/.vimrc': 1 }
 
 let g:signify_sign_overwrite = 1
 
+let g:signify_update_on_bufenter = 1
+
 let g:signify_sign_add               = '+'
 let g:signify_sign_delete            = '-'
 let g:signify_sign_change            = '*'

doc/signify.txt

@@ -118,6 +118,7 @@ Mapping for toggling the plugin for the current buffer only.
     let g:signify_skip_filename = { '/home/user/.vimrc': 1 }
 
 Don't activate the plugin for these filetypes and/or filenames.
+
 NOTE: Filenames have to be absolute paths.
 
 
@@ -126,6 +127,14 @@ NOTE: Filenames have to be absolute paths.
 Overwrite signs set by other plugins by default.
 
 
+    let g:signify_update_on_bufenter = 1
+
+Update signs when entering a buffer.
+
+NOTE: Disable this if you're working in huge repositories and experience
+delays.
+
+
     let g:signify_sign_add               = '+'
     let g:signify_sign_change            = '*'
     let g:signify_sign_change_delete     = '!_'