fix textarea newline handle

[metiftikci]

• Fix cursor position if input newline on middle of lines
• Increment number if numbered list

[metiftikci]

not sure what old code does

got it

[wxiaoguang]

Comment above // a simple approach, otherwise it needs to parse the lines after the current line

[wxiaoguang]

I guess it's not right for this case:

1. a
2. b <---  enter here
3. c

Your result might be

1. a
2. b
3. 
3. c

?

I didn't do that (auto-increase) because it needs a complex algorithm to make it right. And for most cases only using 1. seems clearer and easier when editing, and it doesn't affect the rendering.

---

I added a new test: testInput({value: '1. a\n2. b\n3. c', pos: 4}, {value: '1. a\n2. \n2. b\n3. c', pos: 8});, there are two 2., not sure whether it is what you want.

[metiftikci]

@wxiaoguang should i revert the increase number code or try to implement increasing numbers below?

[wxiaoguang]

@wxiaoguang should i revert the increase number code or try to implement increasing numbers below?

Either is fine, but there are many edge cases, even GitHub doesn't get it completely right, and it would be quite complex, maybe at least hundreds lines of code in my mind.

So at the moment, I would prefer to revert "the increase number"