patch 8.1.2309: compiler warning for argument type

Problem:    Compiler warning for argument type.
Solution:   Use linenr_T and cast to varnumber_T. (John Marriott)

Author: brammool

src/mouse.c

@@ -3019,7 +3019,7 @@ f_getmousepos(typval_T *argvars UNUSED, typval_T *rettv)
     varnumber_T winid = 0;
     varnumber_T winrow = 0;
     varnumber_T wincol = 0;
-    varnumber_T line = 0;
+    linenr_T	line = 0;
     varnumber_T column = 0;
 
     if (rettv_dict_alloc(rettv) != OK)
@@ -3061,7 +3061,7 @@ f_getmousepos(typval_T *argvars UNUSED, typval_T *rettv)
     dict_add_number(d, "winid", winid);
     dict_add_number(d, "winrow", winrow);
     dict_add_number(d, "wincol", wincol);
-    dict_add_number(d, "line", line);
+    dict_add_number(d, "line", (varnumber_T)line);
     dict_add_number(d, "column", column);
 }
 #endif

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2309,
 /**/
     2308,
 /**/