Add pullquote specific styles

[joshdarby]

Changes

This pull request makes the following changes:

• Updated the styling for pull quotes so they look different than normal block quotes.

Before:

After:
Left:

Right:

Full-width:

Wide:

Normal:

Why

For #1699.

Testing/Questions

Features that this PR affects:

• Pull quote blocks.

Questions that need to be answered before merging:

• Should we update any other styles for pull/block quotes?

Steps to test this PR:

1. Add a pull quote block to a post
2. Make sure it looks ok left aligned, right aligned, center aligned, and normal, wide, and full widths.

[benlk]

Previous work in this area: #1687

[benlk]

Those most-recent commits:

• Replace separate pullquote styles in 9749576 with adding the new .wp-block-pullquote class to the existing pullquote styles, similar to how https://github.com/INN/largo/pull/1687/files?file-filters%5B%5D=.less used the existing blockquote styles
• Moves all the pullquote styles shared between Classic and Block Editors from posts-and-pages.less to typography.less, where other blockquote styles live. Block-specific pullquote and blockquote styles remain in blocks.less.

[benlk]

An editor-specific style to override: the border-top and border-bottom on wp-block-pullquote.

[benlk]

I will note that #1748 was already broken in Largo; be30571 just hides the borders in the editor.

@joshdarby do you think we should fix #1748 in this Largo release or in a later one? I wouldn't do it in this PR.

[benlk]

These changes are ready for review by someone not-me.

[joshdarby]

@joshdarby do you think we should fix #1748 in this Largo release or in a later one? I wouldn't do it in this PR.

@benlk I'd prefer to get it done in this release since it is technically a bug, but since it was already broken... Has anyone complained specifically about not being able to specifically choose the color of the border? Worst comes to worst it can be edited by css by whoever wants to change it.

[joshdarby]

@benlk This still works as expected. Are you good with me merging it?

[benlk]

I haven't heard any user complaints about #1748 yet. Let's aim for putting that in the next release, and merging this.