killsnoop: align numbers to the right

Justifications:

https://ux.stackexchange.com/questions/13795/is-there-a-standard-to-left-justify-text-and-right-justify-numeric-values

CHANGELOG.md

@@ -66,7 +66,8 @@ and this project adheres to
   - [#2790](https://github.com/iovisor/bpftrace/pull/2790)
 - Update mdflush.bt to use blkdev.h instead of genhd.h for non-BTF builds.
   - [#2849](https://github.com/iovisor/bpftrace/pull/2849)
-- Add milliseconds to timestamp in `threadsnoop.bt`
+- Add milliseconds to timestamp and align numbers to the right in `threadsnoop.bt`
+  - [#2936](https://github.com/iovisor/bpftrace/pull/2936)
 
 ## [0.19.0] 2023-09-19
 

tools/killsnoop.bt

@@ -18,7 +18,7 @@
 BEGIN
 {
 	printf("Tracing kill() signals... Hit Ctrl-C to end.\n");
-	printf("%-15s %7s %-16s %-4s %-6s %s\n",
+	printf("%-15s %7s %-16s %4s %6s %s\n",
 		"TIME", "PID", "COMM", "SIG", "TPID", "RESULT");
 }
 
@@ -31,7 +31,7 @@ tracepoint:syscalls:sys_enter_kill
 tracepoint:syscalls:sys_exit_kill
 /@tpid[tid]/
 {
-	printf("%-15s %7d %-16s %-4d %-6d %d\n",
+	printf("%-15s %7d %-16s %4d %6d %6d\n",
 		strftime("%H:%M:%S.%f", nsecs),
 		pid, comm, @tsig[tid], @tpid[tid], args.ret);
 	delete(@tpid[tid]);

tools/killsnoop_example.txt

@@ -7,10 +7,10 @@ This traces signals sent via the kill() syscall. For example:
 # ./killsnoop.bt
 Attaching 3 probes...
 Tracing kill() signals... Hit Ctrl-C to end.
-TIME                PID COMM             SIG  TPID   RESULT
-00:09:37.345938   22485 bash             2    23856  0
-00:09:40.838452   22485 bash             2    23856  -3
-00:09:31.437104   22485 bash             15   23814  -3
+TIME                PID COMM              SIG   TPID RESULT
+00:09:37.345938   22485 bash                2  23856      0
+00:09:40.838452   22485 bash                2  23856     -3
+00:09:31.437104   22485 bash               15  23814     -3
 
 The first line showed a SIGINT (2) sent from PID 22485 (a bash shell) to
 PID 23856. The result, 0, means success. The next line shows the same signal