Change wording of field description for tagline

[Presskopp]

This is a follow-up to #57675

I raised my concerns there, but it was too late in the cycle. So here we go:

These are my concerns about the solution we use now:

1) The example is misleading, the tagline should be meaningful, and just not like in the example

Using a unique and descriptive tagline is important for search engine optimization (SEO) purposes, as it helps convey the website's purpose and relevance to both search engines and visitors.

2) The “ and ” could be misunderstood so people would enter quotation marks into the tagline.

This can impact the visual presentation and readability of the tagline to visitors.

To keep the iconic phrase "Just another WordPress site" while being informative at the same time we could formulate:

In a few words, explain what this site is about. We're sure your site is so much more than "Just another WordPress site"

[costdev]

Minor note:

In a few words, explain what this site is about. We're sure your site is so much more than "Just another WordPress site"

"We", "We're" and such are typically removed from user-facing strings, so something like this may be a better basis:

In a few words, explain what this site is about. Your site is so much more than "Just another WordPress site"

[Presskopp]

Good point. ➜

In a few words, explain what this site is about. Your site certainly is so much more than "Just another WordPress site"

[sabernhardt]

Related: #18552

Since I agree with Presskop a lot, I made this PR.

Trac ticket: (https://core.trac.wordpress.org/ticket/58781)

[sabernhardt]

While newer sites would default to an empty field, older sites could still have the previous default tagline. I think "Your site is more than" would be sufficient (without "certainly" or even "so much").

Also, the %s placeholder may not be appropriate with this new sentence. Several of the ​translations it represents do not include "just" and some do not include "another" either. The French translations simply say "A site using WordPress" (or "A site using [Network Title]" in multisite). It also could be troublesome when a vowel would be dropped ("plus que" ➜ "plus qu'un site utilisant WordPress").

[oglekler]

@tobifjellner, I like this idea: #comment:3, but we need to address concerns from #comment:8. I believe that you can clarify things :)

[tobifjellner]

We could more clearly explain how this string is used, and indicate what the default value is (if multisite, the default string could even be modified with the network name). Something like:

Explain in few words what this site is about. Some themes will show this slogan in various places. 
It can also be used by search engines to describe your site. 
The default slogan is (code)%1(/code). 
But you can write a better one.

Thanks @oglekler for the mention. :)

[manfcarlo]

I honestly don't see how the current label is misleading at all. Are you seriously suggesting that users are seeing this note and verbatim typing (or cutting and pasting) "Just another WordPress site." into the text box? Why would anyone do that? I actually think the current label already conveys the same meaning that you are aiming for, because the quality of the example is obvious and it should stimulate the user to write something better.

Perhaps the quotation marks could be replaced with italics, but it's nitpicking and I'd rather just wontfix the ticket.

[sabernhardt]

This still has 2nd-opinion, so I'll move it out of the milestone.