[hx download] allow 'hx download [sha]' syntax (skip 'nightlies' arg)

Author: kLabz

src/HaxeDownload.hx

@@ -27,6 +27,9 @@ class HaxeDownload {
 			case [v] if (SemVer.isValid(v)): downloadRelease(v);
 			case [v, alias] if (SemVer.isValid(v)): downloadRelease(v, alias);
 
+			case [v] if (HaxeNightlies.isValid(v)): downloadNightly(v);
+			case [v, alias] if (HaxeNightlies.isValid(v)): downloadNightly(v, alias);
+
 			case [v] | [v, _]:
 				Utils.displayError('hx download: $v is not a valid release version\n');
 				displayUsage();

src/HaxeNightlies.hx

@@ -9,11 +9,15 @@ class HaxeNightlies {
 	static var ref_check = ~/^[a-f0-9]{7,}$/i;
 
 	public static function resolve(ref:String):String {
-		if (ref_check.match(ref)) return getNightly(ref);
 		if (SemVer.isValid(ref)) return getNightly(ref, true);
+		if (isValid(ref)) return getNightly(ref);
 		return ref;
 	}
 
+	public static function isValid(ref:String):Bool {
+		return ref_check.match(ref);
+	}
+
 	static function getNightly(ref:String, ?isTag:Bool = false):Null<String> {
 		final date = getCommitDate(ref);
 		if (date == null) {