[YAML] indentation style for sequence in mapping

[ikatyang]

I'd like to avoid things like #4251 in the future, let's see how people think about it. We'll decide which style to use before releasing 1.14 based on the 👍/👎 and change the style if one's vote (👍s - 👎s) is greater than another one about 30%, otherwise stay as-is (i.e., do indent).

do indent	do not indent
better readability	no unnecessary indentation
a: - b - c before_script: - command - command - command stages: - test - test - test other: - other - other - other	a: - b - c before_script: - command - command - command stages: - test - test - test other: - other - other - other

[ikatyang]

Please 👍/👎 this comment for the do indent style

[ikatyang]

Please 👍/👎 this comment for the do not indent style

[jaydenseric]

At first glance, I like the indented look. Consistency with Markdown might be a consideration, where the top list level is not indented:

I guess the YAML dashed list items are actually second level though, depending how you look at it.

[ikatyang]

It's time to release 1.14 (#4856) and the voting result is:

• do indent: 24 - 1 = 23
• do not indent: 2 - 14 = -12

so we're going to use do indent style, which is the current implementation.