Fix code formatting in ARM halfword functions

- Convert multi-line comment to single line format
- Add spacing for better readability

Author: hhhh1300

src/arm.c

@@ -339,13 +339,13 @@ int __luh(arm_cond_t cond, arm_reg rd, arm_reg rn, int ofs)
 
 int __lh(arm_cond_t cond, arm_reg rd, arm_reg rn, int ofs)
 {
-    /* ARM signed halfword load (LDRSH)
-     */
+    /* ARM signed halfword load (LDRSH) */
     int opcode = 16 + 8 + 4 + 1;
     if (ofs < 0) {
         opcode -= 8;
         ofs = -ofs;
     }
+
     /* Halfword encoding: split offset into 4-bit high and low parts */
     if (ofs > 255) {
         fatal("Halfword offset too large");