PR: Show a warning telling people how to get out of the pager (IPython console)

[ccordoba12]

Description of Changes

The IPython console has a pager to show long texts in a separate widget to not overflow it with them. It was deactivated by default, but I removed that option with PR #14056 because I thought the pager was broken.

However, our users quickly found out that was not the case and @OverLordGoldDragon suggested we should add a warning to tell people how to get out of the pager. And that's what I've done in this PR.

• Wrote at least one-line docstrings (for any new functions)
• Added unit test(s) covering the changes (if testable)

• Included a screenshot or animation (if affecting the UI, see Licecap)

Issue(s) Resolved

Fixes #14192.

Affirmation

By submitting this Pull Request or typing my (user)name below,
I affirm the Developer Certificate of Origin
with respect to all commits and content included in this PR,
and understand I am releasing the same under Spyder's MIT (Expat) license.

I certify the above statement is true and correct: ccordoba12

[ccordoba12]

@isabela-pf, @juanis2112, I'd like to know your opinion about this feature. Is the idea of a pager grasped by you only by seeing the gif I posted above? That's basically the same experience our users will have.

Unfortunately, I couldn't find a reference in the web we could link to to better describe this.

[OverLordGoldDragon]

Unsure the bar occupying the entire width is the best we can do. Few alternatives:

0. (A) Q return to Console -- (B) Press Q to exit pager; shorter text that helps the below, and ought to suffice as it should be pretty clear to user that "I'm not in console" (and thus the "pager" thing in B is where I'm at).
1. Make the bar <div> half in width, and pin it to the right, away from text, maybe to top-right as user scrolls for new text from bottom.
2. Move info to console row:

3. Mark the Console with a star (like an edited file), and when hovered over, display the tooltip
4. Maybe best of all: autohide the bar after 1-2 secs, then bring it up again only if the user presses any key (as 99% of people will trying to restore the console).

[juanis2112]

Thanks @OverLordGoldDragon, we like your first suggestion. We will make the text be "Press Q to exit pager" but autohiding it can be confusing if people miss the warning. Also the space on top is used when there are several tabs open so using that place for the warning might not be the best idea.

[ccordoba12]

@steff456 suggested that we should only add a blue border around the pager message. This is how things look with that change:

And this how they look with the old style and new text suggested by @OverLordGoldDragon:

I think I prefer the second option because it seems easy to miss the warning with the first (as it looks part of the paged text).

[ccordoba12]

Here it's another suggestion: a red border around the label

[steff456]

By seeing all the options I also prefer the blue background