8_6_installation.md: improve grammar in a note in 8.6 install guide (#1504)

Reword the English in a the note that directs the reader to the Rocky
ISO mirrors, so that the note reads better.

Signed-off-by: Zac Dover <[email protected]>

Author: zdover23

docs/guides/8_6_installation.md

@@ -35,7 +35,7 @@ For example, `Rocky-8.7-x86_64-minimal.iso`
 
 !!! Note
 
-    Rocky project web page has a listing of several mirrors located all over the world. Whenever possible, you should choose the mirror geographically closest to you. The list of official mirrors can be found [here](https://mirrors.rockylinux.org/mirrormanager/mirrors).
+    The Rocky project web page lists several mirrors, which are located around the globe. Choose the mirror geographically closest to you. The list of official mirrors can be found [here](https://mirrors.rockylinux.org/mirrormanager/mirrors).
 
 ## Verifying the Installer ISO File