Docs: Revise comments using “we” in WordPress root directory files.

This updates some inline comments to better match the guidelines and recommendations set forth in the make/core and make/docs handbooks:

> In general, use second person in your documentation. Second person depicts a friendly tone, with a perfect focus on the reader. In addition to this, directly addressing the reader helps avoid passive voice; thereby preventing unwanted confusion.
> ...
> the word “we” should be avoided (...) unless its made very clear which group is speaking.

Includes:
* Replacing first-person usage of "we" with second person point of view.
* Making small clarification adjustments where the voice is much too casual or lacks clear context, especially for non-native English speakers.

References:
* [https://make.wordpress.org/docs/style-guide/language-grammar/grammatical-person/ Style Guide: Grammatical person]
* [https://make.wordpress.org/docs/handbook/documentation-team-handbook/handbooks-style-and-formatting-guide/ Handbooks & HelpHub Style and Formatting Guide]
* [https://make.wordpress.org/core/handbook/best-practices/post-comment-guidelines/#style-and-substance Post & Comment Guidelines: Style and Substance]

Follow-up to [2176], [3430], [4676], [6009], [7991], [12688], [12762], [26008], [28978], [44488], [44962], [51979], [53131], [53132], [53156], [53131], [54200].

Props ironprogrammer, costdev, jorbin, SergeyBiryukov.
See #57052.
Built from https://develop.svn.wordpress.org/trunk@54866


git-svn-id: http://core.svn.wordpress.org/trunk@54418 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-trackback.php

@@ -76,7 +76,7 @@ if ( function_exists( 'mb_convert_encoding' ) ) {
 	$blog_name = mb_convert_encoding( $blog_name, get_option( 'blog_charset' ), $charset );
 }
 
-// Now that mb_convert_encoding() has been given a swing, we need to escape these three.
+// Escape values to use in the trackback.
 $title     = wp_slash( $title );
 $excerpt   = wp_slash( $excerpt );
 $blog_name = wp_slash( $blog_name );