Change gendered terms to be gender-neutral (#21325)

Some typos are also fixed.

docs/CODING_STYLE.md

@@ -297,7 +297,7 @@ SPDX-License-Identifier: LGPL-2.1-or-later
   with a more brutal `assert()`. We are more forgiving to public users than for
   ourselves! Note that `assert()` and `assert_return()` really only should be
   used for detecting programming errors, not for runtime errors. `assert()` and
-  `assert_return()` by usage of `_likely_()` inform the compiler that he should
+  `assert_return()` by usage of `_likely_()` inform the compiler that it should
   not expect these checks to fail, and they inform fellow programmers about the
   expected validity and range of parameters.
 

docs/PREDICTABLE_INTERFACE_NAMES.md

@@ -54,7 +54,7 @@ With this new scheme you now get:
 * The same on all distributions that adopted systemd/udev
 * It's easy to opt out of the scheme (see below)
 
-Does this have any drawbacks? Yes, it does. Previously it was practically guaranteed that hosts equipped with a single ethernet card only had a single `eth0` interface. With this new scheme in place, an administrator now has to check first what the local interface name is before he can invoke commands on it where previously he had a good chance that `eth0` was the right name.
+Does this have any drawbacks? Yes, it does. Previously it was practically guaranteed that hosts equipped with a single ethernet card only had a single `eth0` interface. With this new scheme in place, an administrator now has to check first what the local interface name is before they can invoke commands on it, where previously they had a good chance that `eth0` was the right name.
 
 
 ## I don't like this, how do I disable this?