patch 8.2.0106: printf formats are not exactly right

Problem:    Printf formats are not exactly right.
Solution:   Adjust signed/unsigned conversions. (Frazer Clews, closes #5456)
diff --git a/src/ui.c b/src/ui.c
index f4f7bcf..151857f 100644
--- a/src/ui.c
+++ b/src/ui.c
@@ -1168,7 +1168,7 @@
     cb->prev = cb->start;
 
 #ifdef DEBUG_SELECTION
-    printf("Selection started at (%u,%u)\n", cb->start.lnum, cb->start.col);
+    printf("Selection started at (%ld,%d)\n", cb->start.lnum, cb->start.col);
 #endif
 }
 
@@ -1203,7 +1203,7 @@
 	}
 
 #ifdef DEBUG_SELECTION
-	printf("Selection ended: (%u,%u) to (%u,%u)\n", cb->start.lnum,
+	printf("Selection ended: (%ld,%d) to (%ld,%d)\n", cb->start.lnum,
 		cb->start.col, cb->end.lnum, cb->end.col);
 #endif
 	if (clip_isautosel_star()
@@ -1347,7 +1347,7 @@
     cb->prev.col  = col;
 
 #ifdef DEBUG_SELECTION
-	printf("Selection is: (%u,%u) to (%u,%u)\n", cb->start.lnum,
+	printf("Selection is: (%ld,%d) to (%ld,%d)\n", cb->start.lnum,
 		cb->start.col, cb->end.lnum, cb->end.col);
 #endif
 }