[Plugin] Support auto close and rename tag

[NNBnh]

Following issue #46:

Pepper would be great if it have the quality-of-life-improvement features from two of the most popular VScode plugins: Auto Close Tag and Auto Rename Tag:

Auto Close Tag

From the "Auto Rename Tag" VScode plugin:

Automatically add HTML/XML close tag, same as Visual Studio IDE or Sublime Text does:

• Automatically add closing tag when you type in the closing bracket of the opening tag
• After closing tag is inserted, the cursor is between the opening and closing tag
• Set the tag list that would not be auto closed
• Automatically close self-closing tag
• Support auto close tag as Sublime Text 3
• Use Keyboard Shortcut or Command Palette to add close tag manually

Auto Rename Tag:

From the "Auto Rename Tag" VScode plugin:

When you rename one HTML/XML tag, automatically rename the paired HTML/XML tag

If you find this suggestion it's suitable to be built-in with the editor, feel free to label this issue with "Plugin" or "Plugin Idea".

[vamolessa]

I feel like auto-close could be implemented through a plugin:
It would override the on_keys and watches for a > key event.
Then it would check if the current buffer's path has a html or xml extension.
If it does, it'd check for each cursor if it's at the end of a tag and, if it is, it would insert the corresponding text right after it.

The auto rename also could be made via a plugin that watches the on_keys event.
However, you could also achieve a similar result by using multiple cursors:

• put the cursor on top of one of the tags
• press N (or P)
• press N if the next tag is bellow the cursor or P if it is above
• then awi to select all whole words, delete them, and then enter insert mode with multiple cursors
  Then pressing <esc> twice will return to normal mode and collapse all cursors into only the main cursor.