notcurses_cursor_yx ought be const

USAGE.md

@@ -300,7 +300,7 @@ int notcurses_refresh(struct notcurses* n, unsigned* restrict y, unsigned* restr
 int notcurses_cursor_enable(struct notcurses* nc, int y, int x);
 
 // Get the current location of the terminal's cursor, whether visible or not.
-int notcurses_cursor_yx(struct notcurses* nc, int* y, int* x);
+int notcurses_cursor_yx(const struct notcurses* nc, int* y, int* x);
 
 // Disable the hardware cursor. It is an error to call this while the
 // cursor is already disabled.

doc/man/man3/notcurses_init.3.md

@@ -49,7 +49,7 @@ typedef struct notcurses_options {
 
 **int notcurses_cursor_enable(struct notcurses* ***nc***, int ***y***, int ***x***);**
 
-**int notcurses_cursor_yx(struct notcurses* ***nc***, int* ***y***, int* ***x***);**
+**int notcurses_cursor_yx(const struct notcurses* ***nc***, int* ***y***, int* ***x***);**
 
 **int notcurses_cursor_disable(struct notcurses* ***nc***);**
 

include/notcurses/notcurses.h

@@ -3637,7 +3637,7 @@ API int notcurses_cursor_enable(struct notcurses* nc, int y, int x)
   __attribute__ ((nonnull (1)));
 
 // Get the current location of the terminal's cursor, whether visible or not.
-API int notcurses_cursor_yx(struct notcurses* nc, int* y, int* x)
+API int notcurses_cursor_yx(const struct notcurses* nc, int* y, int* x)
   __attribute__ ((nonnull (1)));
 
 // Disable the hardware cursor. It is an error to call this while the

src/lib/render.c

@@ -1726,7 +1726,7 @@ int ncdirect_set_fg_rgb(ncdirect* nc, unsigned rgb){
   return 0;
 }
 
-int notcurses_cursor_yx(notcurses* nc, int* y, int* x){
+int notcurses_cursor_yx(const notcurses* nc, int* y, int* x){
   *y = nc->rstate.y;
   *x = nc->rstate.x;
   return 0;