Fix return type annotation (#613)

* Fix return type annotation

* BC with tools that do not support PHPStan annotations

Co-authored-by: William Desportes <williamdes@wdes.fr>

---------

Co-authored-by: William Desportes <williamdes@wdes.fr>
Co-authored-by: Nicola Asuni <nicolaasuni@users.noreply.github.com>

tcpdf.php

@@ -4102,6 +4102,7 @@ public function setTextColor($col1=0, $col2=-1, $col3=-1, $col4=-1, $ret=false,
 	 * @param float $fontsize Font size in points. The default value is the current size.
 	 * @param boolean $getarray if true returns an array of characters widths, if false returns the total length.
 	 * @return float[]|float total string length or array of characted widths
+	 * @phpstan-return ($getarray is true ? float[] : float) total string length or array of characted widths
 	 * @author Nicola Asuni
 	 * @public
 	 * @since 1.2
@@ -4118,6 +4119,7 @@ public function GetStringWidth($s, $fontname='', $fontstyle='', $fontsize=0, $ge
 	 * @param float $fontsize Font size in points. The default value is the current size.
 	 * @param boolean $getarray if true returns an array of characters widths, if false returns the total length.
 	 * @return float[]|float total string length or array of characted widths
+	 * @phpstan-return ($getarray is true ? float[] : float) total string length or array of characted widths
 	 * @author Nicola Asuni
 	 * @public
 	 * @since 2.4.000 (2008-03-06)