pages*/*: update outdated pages, pages/*: fix placeholders (#14171)

pages/linux/gedit.md

@@ -13,7 +13,7 @@
 
 - Open a text file with a specific encoding:
 
-`gedit --encoding={{UTF-8}} {{path/to/file}}`
+`gedit --encoding {{UTF-8}} {{path/to/file}}`
 
 - Display a list of supported encodings:
 

pages/linux/journalctl.md

@@ -5,11 +5,11 @@
 
 - Show all messages with priority level 3 (errors) from this [b]oot:
 
-`journalctl -b --priority={{3}}`
+`journalctl -b --priority=3`
 
 - Delete journal logs which are older than 2 days:
 
-`journalctl --vacuum-time={{2d}}`
+`journalctl --vacuum-time=2d`
 
 - Show only the last N li[n]es and [f]ollow new messages (like `tail -f` for traditional syslog):