setarch: add page (#16598)

* setarch: add page

* Update setarch.md

Co-authored-by: Wiktor Perskawiec <git@spageektti.cc>

---------

Co-authored-by: Wiktor Perskawiec <git@spageektti.cc>

pages/linux/setarch.md

@@ -0,0 +1,25 @@
+# setarch
+
+> Change the reported architecture for a program's execution, primarily used to modify how programs behave based on system architecture.
+> Useful for compatibility testing or running legacy applications.
+> More information: <https://manned.org/setarch.8>.
+
+- Run a command as if the machine architecture is `i686` (useful for running 32-bit apps on a 64-bit kernel):
+
+`setarch i686 {{command}}`
+
+- Run a shell with the `x86_64` architecture:
+
+`setarch x86_64 {{bash}}`
+
+- Disable randomization of the virtual address space:
+
+`setarch {{linux32}} {{[-R|--addr-no-randomize]}} {{command}}`
+
+- List supported architectures:
+
+`setarch --list`
+
+- Display help:
+
+`setarch {{[-h|--help]}}`