Improve Post Password Form Message

[Tyrannous]

The current sentence displayed on password-protected posts is:

This content is password protected. To view it please enter your password below:

I’d like to propose updating this message to:

This content is password-protected. To view it, please enter the password below.

Changes made:

1. Grammar and punctuation correction: Added a hyphen in “password-protected” (as it is a compound adjective) and a comma before “please”.
2. Clarity: Replaced “your password” with “the password” — since it refers to the password set by the post author, not the user’s own.
3. Consistency: Changed the colon at the end to a full stop. The colon is redundant because the form label for the password field already includes one, causing a slightly awkward duplication.

This PR updates the post password form message from:

This content is password protected. To view it please enter your password below:

to:

This content is password-protected. To view it, please enter the password below.

Trac ticket: https://core.trac.wordpress.org/ticket/63301

[SergeyBiryukov]

In 60222:

Text Changes: Improve the post password form message for clarity and consistency.

Follow-up to [323], [394], [9138], [25582], [59736].

Props Tyrannous.
Fixes #63301.