"resource overlay [..] does not require rooted device" is misleading wording

[infinity0]

As discussed in #8 I think the current wording is misleading, because:

1. it confuses the issue of how the overlay works to enable Bromite, vs the issue of how to install the overlay
2. "rooted device" is ambiguous and might make a user think root access is not used at all during the installation process, or that the overlay doesn't effectively have system/root privileges as it modifies a vital part of the system. Both of these beliefs are incorrect.

In #8 I suggested amending the current sentence to simply say:

This method is more straightforward and elegant, as it does not require the
tedious process of patching the system framework itself manually.

This addresses (1) by only talking about how the overlay works, after it is installed. Then I suggested to elaborate the installation process in a separate paragraph, addressing (2):

Our officially-endorsed and tested way for installing this overlay is [via
recovery](#installation), which allows you to avoid rooting your main system
e.g. with Magisk. (You still need to unlock your bootloader, and install a
custom ROM that allows addons to be installed via recovery, which provides
temporary root access to the addon installation script.)

Granted, this is quite long and could be shortened, e.g. to something like:

Our official well-tested method for installing this overlay is [via
recovery](#installation), which allows you to avoid rooting your main system,
by providing temporary root access to our addon installation script only during
recovery.

BTW, the existing popular Androidacy module in fact uses an overlay itself. The problem is that it does a lot of other unnecessary things during installation such as download Bromite from the internet, with no well-defined update process for it, which is why I did #8 as an alternative. The point is, whether or not something "requires Magisk" or "requires a rooted device" is an aspect of the installation process, not of the overlay itself.