Document some pokenav and region map

ld_script.txt

@@ -302,7 +302,7 @@ SECTIONS {
         src/mirage_tower.o(.text);
         src/berry_fix_program.o(.text);
         src/pokemon_summary_screen.o(.text);
-        src/unk_pokedex_area_screen_helper.o(.text);
+        src/pokedex_area_region_map.o(.text);
         src/battle_pyramid_bag.o(.text);
         src/pokenav.o(.text);
         src/pokenav_main_menu.o(.text);
@@ -659,7 +659,7 @@ SECTIONS {
         src/mirage_tower.o(.rodata);
         src/berry_fix_program.o(.rodata);
         src/pokemon_summary_screen.o(.rodata);
-        src/unk_pokedex_area_screen_helper.o(.rodata);
+        src/pokedex_area_region_map.o(.rodata);
         src/battle_pyramid_bag.o(.rodata);
         src/pokenav.o(.rodata);
         src/pokenav_main_menu.o(.rodata);