vi-mode show indicator on zle-line-init and SIGWINCH (#6449)

plugins/vi-mode/vi-mode.plugin.zsh

@@ -4,9 +4,15 @@ function zle-keymap-select() {
   zle -R
 }
 
+# Ensures that MODE_INDITCATOR is displayed on terminal start up.
+function zle-line-init() {
+  zle reset-prompt
+}
+
 # Ensure that the prompt is redrawn when the terminal size changes.
 TRAPWINCH() {
   zle &&  zle -R
+  zle reset-prompt
 }
 
 zle -N zle-keymap-select