fix: inline codes now exitable with right arrow key and inclusive

[Palanikannan1437]

Description

Inline code blocks are now exitable with the right arrow key and inclusive at the same time.

Key behaviours

1. Only recognises inline code blocks if typed in the format left prefix (backtick)--> inline code text --> right prefix(backtick), this is the intended behaviour incase as explained in fix: inline code blocks, code blocks and links have saner behaviour #3318
2. Inline code blocks can be triggered by using the bubble menu on selecting text (regression) in Rich text editors.
3. To exit a code block, use the right arrow key and to get inside and start typing again use the left arrow key (backspace won't work as it's intended)
4. Added a behaviour in which-->
   1. If you select any amounts of text and then click on the button for toggling code, then it'll make it inline code.
   2. If your cursor is just at some node and you click on button for toggling code then it'll make it a code block and if you click on it again it'll simply turn it into a paragraph node.
   3. If you select text inside a code block, then click on button for toggling code, it'll simply turn it into a paragraph node.

Demo

1. For code blocks exiting

inline-code-exitable.mp4

2. For toggling code block in pages, issues and comments

toggle.code.mp4