dnf: add history example (#8220)

The history command shows well formatted installation log. Gives quick idea about what has happened so far.
Also, retrieve the list and repeat the same operations on the new system to get up and running quickly.

pages/linux/dnf.md

@@ -15,14 +15,10 @@
 
 `dnf info {{package}}`
 
-- Install a new package:
+- Install a new package (use `-y` to confirm all prompts automatically):
 
 `sudo dnf install {{package}}`
 
-- Install a new package and assume yes to all questions:
-
-`sudo dnf -y install {{package}}`
-
 - Remove a package:
 
 `sudo dnf remove {{package}}`
@@ -34,3 +30,7 @@
 - Find which packages provide a given file:
 
 `dnf provides {{file}}`
+
+- View all past operations:
+
+`dnf history`