tweaks: capitalize the word "nano" when at the start of a sentence

As is done in two other messages.

src/utils.c

@@ -357,7 +357,7 @@ void *nmalloc(size_t howmuch)
 	void *r = malloc(howmuch);
 
 	if (r == NULL && howmuch != 0)
-		die(_("nano is out of memory!\n"));
+		die(_("Nano is out of memory!\n"));
 
 	return r;
 }
@@ -369,7 +369,7 @@ void *nrealloc(void *ptr, size_t howmuch)
 	void *r = realloc(ptr, howmuch);
 
 	if (r == NULL && howmuch != 0)
-		die(_("nano is out of memory!\n"));
+		die(_("Nano is out of memory!\n"));
 
 	return r;
 }