Plugins: vi-mode: Add first README file

plugins/vi-mode/README.md

+vi-mode
+=======
+This plugin increase `vi-like` zsh functionality.
+
+Use `ESC` or `CTRL-[` to enter `Normal mode`.
+
+
+History
+-------
+
+- `ctrl-p` : Previous command in history
+- `ctrl-n` : Next command in history
+- `/`      : Search backward in history
+- `n`      : Repeat the last `/`
+
+
+Mode indicators
+---------------
+
+*Normal mode* is indicated with red `<<<` mark at the right prompt, when it
+wasn't defined by theme.
+
+
+Vim edition
+-----------
+
+- `v`   : Edit current command line in Vim
+
+
+Movement
+--------
+
+- `$`   : To the end of the line
+- `^`   : To the first non-blank character of the line
+- `0`   : To the first character of the line
+- `w`   : [count] words forward
+- `W`   : [count] WORDS forward
+- `e`   : Forward to the end of word [count] inclusive
+- `E`   : Forward to the end of WORD [count] inclusive
+- `b`   : [count] words backward
+- `B`   : [count] WORDS backward
+- `t{char}`   : Till before [count]'th occurrence of {char} to the right
+- `T{char}`   : Till before [count]'th occurrence of {char} to the left
+- `f{char}`   : To [count]'th occurrence of {char} to the right
+- `F{char}`   : To [count]'th occurrence of {char} to the left
+- `;`   : Repeat latest f, t, F or T [count] times
+- `,`   : Repeat latest f, t, F or T in opposite direction
+
+
+Insertion
+---------
+
+- `i`   : Insert text before the cursor
+- `I`   : Insert text before the first character in the line
+- `a`   : Append text after the cursor
+- `A`   : Append text at the end of the line
+- `o`   : Insert new command line below the current one
+- `O`   : Insert new command line above the current one
+
+
+Delete and Insert
+-----------------
+
+- `ctrl-h`      : While in *Insert mode*: delete character after the cursor
+- `ctrl-w`      : While in *Insert mode*: delete word after the cursor
+- `d{motion}`   : Delete text that {motion} moves over
+- `dd`          : Delete line
+- `D`           : Delete characters under the cursor until the end of the line
+- `c{motion}`   : Delete {motion} text and start insert
+- `cc`          : Delete line and start insert
+- `C`           : Delete to the end of the line and start insert
+- `r{char}`     : Replace the character under the cursor with {char}
+- `R`           : Enter replace mode: Each character replaces existing one
+- `x`           : Delete [count] characters under and after the cursor
+- `X`           : Delete [count] characters before the cursor