py/builtinhelp: Change signature of help text var from pointer to array.

As a pointer (const char *) it takes up an extra word of storage which is
in RAM.

ports/cc3200/misc/help.c

@@ -27,6 +27,6 @@
 
 #include "py/builtin.h"
 
-const char *cc3200_help_text = "Welcome to MicroPython!\n"
+const char cc3200_help_text[] = "Welcome to MicroPython!\n"
                                 "For online help please visit http://micropython.org/help/.\n"
                                 "For further help on a specific object, type help(obj)\n";

ports/esp8266/help.c

@@ -26,7 +26,7 @@
 
 #include "py/builtin.h"
 
-const char *esp_help_text =
+const char esp_help_text[] =
 "Welcome to MicroPython!\n"
 "\n"
 "For online docs please visit http://docs.micropython.org/en/latest/esp8266/ .\n"

ports/stm32/help.c

@@ -26,7 +26,7 @@
 
 #include "py/builtin.h"
 
-const char *stm32_help_text =
+const char stm32_help_text[] =
 "Welcome to MicroPython!\n"
 "\n"
 "For online help please visit http://micropython.org/help/.\n"

ports/teensy/help.c

@@ -26,7 +26,7 @@
 
 #include "py/builtin.h"
 
-const char *teensy_help_text =
+const char teensy_help_text[] =
 "Welcome to MicroPython!\n"
 "\n"
 "For online help please visit http://micropython.org/help/.\n"

ports/zephyr/help.c

@@ -26,7 +26,7 @@
 
 #include "py/builtin.h"
 
-const char *zephyr_help_text =
+const char zephyr_help_text[] =
 "Welcome to MicroPython!\n"
 "\n"
 "Control commands:\n"

py/builtin.h

@@ -118,6 +118,6 @@ extern const mp_obj_module_t mp_module_webrepl;
 extern const mp_obj_module_t mp_module_framebuf;
 extern const mp_obj_module_t mp_module_btree;
 
-extern const char *MICROPY_PY_BUILTINS_HELP_TEXT;
+extern const char MICROPY_PY_BUILTINS_HELP_TEXT[];
 
 #endif // MICROPY_INCLUDED_PY_BUILTIN_H

py/builtinhelp.c

@@ -32,7 +32,7 @@
 
 #if MICROPY_PY_BUILTINS_HELP
 
-const char *mp_help_default_text =
+const char mp_help_default_text[] =
 "Welcome to MicroPython!\n"
 "\n"
 "For online docs please visit http://docs.micropython.org/\n"