About: Use $display_version in headings

[mukesh27]

As per [44733] about.php page changeset we have to remove $display_version as it was no longer in used in below statement.

<p class="about-text"><?php printf( __( 'Thank you for updating to the latest version!' ), $display_version ); ?></p>

Replace to

<p class="about-text"><?php _e( 'Thank you for updating to the latest version!' ); ?></p>

[mukesh27]

Patch.

[SergeyBiryukov]

Since [45271] and [45292], the tagline contains a hardcoded WordPress 5.2 version.

Per ​Slack discussion, we should restore WordPress %s here to include minor versions.

[desrosj]

46408.2.diff​ restores the placeholder for $display_version.

[ocean90]

#47241 was marked as a duplicate.

[desrosj]

46408.3.diff​ adds translator comments.

[desrosj]

I accidentally included some package-lock.json differences in 46408.3.diff​. 46408.4.diff​ removes those.

I think this is good to go. Marking commit pending a second set of eyes from @SergeyBiryukov.

[SergeyBiryukov]

In 45338:

Help/About: Restore placeholder for WordPress version in tagline on About, Credits, and Freedoms pages to include minor versions.

Props desrosj, mukesh27.
Fixes #46408.

[SergeyBiryukov]

In 45339:

Help/About: Restore placeholder for WordPress version in tagline on About, Credits, and Freedoms pages to include minor versions.

Props desrosj, mukesh27.
Merges [45338] to the 5.2 branch.
Fixes #46408.

[ocean90]

#46776 was marked as a duplicate.