Make Time work with std/strformat (#21409)

* Add test case

* Remove formatValue template for `Time`

It didn't handle empty specifier correctly which caused it to be blank with strformat

lib/pure/times.nim

@@ -2109,7 +2109,7 @@ proc format*(dt: DateTime, f: static[string]): string {.raises: [].} =
   const f2 = initTimeFormat(f)
   result = dt.format(f2)
 
-proc formatValue*(result: var string; value: DateTime, specifier: string) =
+proc formatValue*(result: var string; value: DateTime | Time, specifier: string) =
   ## adapter for strformat. Not intended to be called directly.
   result.add format(value,
     if specifier.len == 0: "yyyy-MM-dd'T'HH:mm:sszzz" else: specifier)
@@ -2133,10 +2133,6 @@ proc format*(time: Time, f: static[string], zone: Timezone = local()): string
   const f2 = initTimeFormat(f)
   result = time.inZone(zone).format(f2)
 
-template formatValue*(result: var string; value: Time, specifier: string) =
-  ## adapter for `strformat`. Not intended to be called directly.
-  result.add format(value, specifier)
-
 proc parse*(input: string, f: TimeFormat, zone: Timezone = local(),
     loc: DateTimeLocale = DefaultLocale): DateTime
     {.raises: [TimeParseError, Defect].} =

tests/stdlib/t21406.nim

@@ -0,0 +1,5 @@
+import std/[times, strformat]
+import std/assertions
+
+doAssert fmt"{getTime()}" == $getTime()
+doAssert fmt"{now()}" == $now()