manual: Update with keybinding and vi prompt

manual/src/SUMMARY.md

@@ -12,7 +12,8 @@
     - [Multi-line Arguments](misc/04-multiargs.md)
     - [Multi-line Strings](misc/05-multiline-strings.md)
     - [Prompt Function](misc/06-prompt_fn.md)
-    - [General Tips](misc/07-general.md)
+    - [Key Bindings](misc/07-keybindings.md)
+    - [General Tips](misc/08-general.md)
 
 - [Variables](variables/00-variables.md)
 

manual/src/misc/07-keybindings.md

+# Key Bindings
+
+There are two pre-set key maps available: Emacs (default) and Vi.
+You can switch between them with the `keybindings` built-in command.
+
+```
+keybindings vi
+keybindings emacs
+```
+
+## Vi Mode Prompt Indicators
+
+In the Vi mode, you can define the displayed indicator for normal and insert modes
+with the following variables:
+
+```
+$ export VI_NORMAL = "[=] "
+$ export VI_INSERT = "[+] "
+$ keybindings vi
+[+] $
+```