Changes to 2 English source files

[Jennifer Hodgdon]

I wanted to let you know that on these two issues:
https://www.drupal.org/project/user_guide/issues/3017104

https://www.drupal.org/project/user_guide/issues/3012035

we made changes to a few English source file, as follows:

prevent-cache-clear.txt

  Added a section about using the rebuild.php script to do a cache rebuild.

install-prepare.txt
install-run.txt

   Minor changes to how we reference making sure the PHP and other server software is installed

install-requirements.txt

  Updated the notes about PHP requirements to talk about memory and PHP extensions

Here are the commits for reference:
https://cgit.drupalcode.org/user_guide/commit/?id=aed2ac3

https://cgit.drupalcode.org/user_guide/commit/?id=b13c39a 

Suggested actions to respond to this change to each file in each language would be either:
a) If the file hasn't been translated yet, copy the English source file to your language directory and commit it.
b) If the file has already been translated, open a new issue to revise the translation.