doc: fix style bug on version link dropdown

[chris--young]

I noticed a minor styling bug while working on #15670 that this pr will fix.

Before:

After:

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• documentation is changed or added
• commit message follows commit guidelines

Affected core subsystem(s)

doc

[silverwind]

I also noticed this and included some fixes for it in #15660, thought my approach is a bit different. I set box-sizing: border-box, fixed the #gtoc li selector so it doesn't affect the dropdown and then cleaned up the style of ol.version-picker.

[chris--young]

That’s cool. I have no strong opinions one way or the other, would just like to see whatever approach we go with make it into the back port to v6.

I did already sneak this into #15670

[silverwind]

I think the approach here is not the right one. The root of the issue is that #gtoc li affects the dropdown items while it should not. Changing the selector #gtoc li to #gtoc > ul > li is a better fix. If you'd like to change this here, I will remove the change in my other PR.

[chris--young]

Let’s keep it in your’s.