suspend: add page (#15247)

pages/common/suspend.md

@@ -0,0 +1,16 @@
+# suspend
+
+> Suspend the execution of the current shell.
+> More information: <https://www.gnu.org/software/bash/manual/bash.html#index-suspend>.
+
+- Suspend the current shell (useful for when you are in nested shells like `su`):
+
+`{{bash}} <Enter> suspend`
+
+- Run in a separate terminal to continue from suspension if `suspend` was used in a non-nested shell:
+
+`pkill -CONT bash`
+
+- Force suspension even if this would lock you out of the system:
+
+`suspend -f`