doc: do not compact stability text to one line

Previously, stability descriptions were strung together as one long horizontal row at https://nodejs.org/api/documentation.html. Now, the text now will auto-expand vertically, so you can see all of the text at once.

Note that the CSS options for how to handle this are somewhat constrained since the paragraphs are being rendered through pre elements, and the third party syntax highlighting library does apply its own styling.

Before: https://cl.ly/2w2O0z1T2o0Y After: https://cl.ly/3z1i1t2D2r41

This does not affect the stability boxes for features, as those were not previously affected by this bug, and are only a few words long.

Checklist

• documentation is changed or added
• commit message follows commit guidelines

Affected core subsystem(s)

doc