Exclude newline character from colorized output

Coloring the newline character results in the terminal cursor becoming
colored when the final line in the interdiff is colored.

Fix this by not coloring the newline character.

Author: kerneltoast

src/interdiff.c

@@ -1143,7 +1143,8 @@ trim_context (FILE *f /* positioned at start of @@ line */,
 				fwrite (line, (size_t) got, 1, out);
 				continue;
 			}
-			print_color (out, type, "%s", line);
+			print_color (out, type, "%.*s", (int) got - 1, line);
+			fputc ('\n', out);
 		}
 	}