Update the update-php URL and add annotation

[afragen]

Update previously committed instances of https://wordpress.org/support/update-php to utilize the new wp_get_update_php_url() introduced in r44476

[afragen]

Use wp_get_update_php_url()

[afragen]

added wp_get_update_php_annotation()

[afragen]

changed function name to wp_update_php_annotation() as it doesn't return a value so get is incorrect

[afragen]

Updated @return docBlock, I hope I got this one right

[pento]

Adding to 5.1 milestone for consideration.

[flixos90]

45986.5.diff​ enhances the previous patches in the following ways:

• Only show the information about updating PHP if current_user_can( 'update_php' ). This was missed in the original ticket.
• In wp-admin/includes/plugin-install.php, ensure that calling wp_update_php_annotation() does not cause invalid HTML markup with nested p tags.
• In wp-admin/includes/plugin-install.php, get rid of the "so unfortunately you cannot install it" part of the message. This makes it consistent with the message about the WordPress version and prevents inaccuracies, as this information may also be displayed when the plugin is already installed.

[flixos90]

In 44627:

Plugins: Use centralized API to display information about updating PHP when a plugin requires a higher version.

This changeset uses the API functions introduced in [44476] to link to the resource about updating PHP when highlighting a plugin's required PHP version is not met. It furthermore expands them, introducing a new wp_update_php_annotation() function that prints the markup to indicate that the default URL has been altered by the web host, allowing it to be reused universally.

Furthermore, this changeset adds missing update_php capability checks before displaying the information about updating PHP.

Props afragen.
Fixes #45986. See #43986, #45686.