at, atq, atrm, batch: add more information link (#5640)

pages/common/at.md

@@ -2,7 +2,7 @@
 
 > Execute commands once at a later time.
 > Service atd (or atrun) should be running for the actual executions.
-> More information: <https://www.man7.org/linux/man-pages/man1/at.1p.html>.
+> More information: <https://man.archlinux.org/man/at.1>.
 
 - Execute commands from standard input in 5 minutes (press `Ctrl + D` when done):
 

pages/common/atq.md

@@ -1,6 +1,7 @@
 # atq
 
 > Show jobs scheduled by `at` or `batch` commands.
+> More information: <https://man.archlinux.org/man/at.1>.
 
 - Show the current user's scheduled jobs:
 

pages/common/atrm.md

@@ -2,6 +2,7 @@
 
 > Remove jobs scheduled by `at` or `batch` commands.
 > To find job numbers use `atq`.
+> More information: <https://man.archlinux.org/man/at.1>.
 
 - Remove job number 10:
 

pages/common/batch.md

@@ -2,6 +2,7 @@
 
 > Execute commands at a later time when the system load levels permit.
 > Service atd (or atrun) should be running for the actual executions.
+> More information: <https://man.archlinux.org/man/at.1>.
 
 - Execute commands from standard input (press `Ctrl + D` when done):