feat(tools/when): try to parse input as one segment first

Before getting clever about durations & stuff, try to parse the whole thing at
once. This is useful for plain timestamps that contain spaces, like `2024-01-01
15:00:01` for example.

Change-Id: I50b0ee8488c153b4e6db75abaea409d55c0b92d6
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11600
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI

tools/when/when.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"strconv"
+	"strings"
 	"time"
 )
 
@@ -107,6 +108,13 @@ func main() {
 	var err error
 	var haveTime, haveDuration bool
 
+	// Try to parse entire input as one full thing, before getting more
+	// clever.
+	if t, err = parseTime(strings.Join(os.Args[1:], " ")); err == nil {
+		printTime(t)
+		return
+	}
+
 	for _, arg := range os.Args[1:] {
 		if !haveTime {
 			if t, err = parseTime(arg); err == nil {