doc/develop/application: Replace native_posix w native_sim

As we are replacing native_posix with native_sim, let's
use native_sim instead of native_posix as example platform.

Signed-off-by: Alberto Escolar Piedras <[email protected]>

Author: aescolar

doc/develop/application/index.rst

@@ -706,20 +706,20 @@ Given the following example project layout:
    ├── prj.conf
    ├── prj_mouse.conf
    ├── boards
-   │   ├── native_posix.overlay
+   │   ├── native_sim.overlay
    │   └── qemu_cortex_m3_mouse.overlay
    └── src
        └── main.c
 
-* If this is built normally without ``FILE_SUFFIX`` being defined for ``native_posix`` then
-  ``prj.conf`` and ``boards/native_posix.overlay`` will be used.
+* If this is built normally without ``FILE_SUFFIX`` being defined for ``native_sim`` then
+  ``prj.conf`` and ``boards/native_sim.overlay`` will be used.
 
 * If this is build normally without ``FILE_SUFFIX`` being defined for ``qemu_cortex_m3`` then
   ``prj.conf`` will be used, no application devicetree overlay will be used.
 
-* If this is built with ``FILE_SUFFIX`` set to ``mouse`` for ``native_posix`` then
-  ``prj_mouse.conf`` and ``boards/native_posix.overlay`` will be used (there is no
-  ``native_posix_mouse.overlay`` file so it falls back to ``native_posix.overlay``).
+* If this is built with ``FILE_SUFFIX`` set to ``mouse`` for ``native_sim`` then
+  ``prj_mouse.conf`` and ``boards/native_sim.overlay`` will be used (there is no
+  ``native_sim_mouse.overlay`` file so it falls back to ``native_sim.overlay``).
 
 * If this is build with ``FILE_SUFFIX`` set to ``mouse`` for ``qemu_cortex_m3`` then
   ``prj_mouse.conf`` will be used and ``boards/qemu_cortex_m3_mouse.overlay`` will be used.