[BUGFIX] Fix type errors in PHP strict mode (#695)

This is the backport of #664.

Author: oliverklee

CHANGELOG.md

@@ -19,6 +19,7 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 
 ### Fixed
 
+- Fix type errors in PHP strict mode (#695)
 - Fix comment parsing to support multiple comments (#671)
 
 ## 8.6.0

src/Value/Size.php

@@ -223,7 +223,7 @@ public function render(OutputFormat $oOutputFormat)
         $l = localeconv();
         $sPoint = preg_quote($l['decimal_point'], '/');
         $sSize = preg_match("/[\d\.]+e[+-]?\d+/i", (string)$this->fSize)
-            ? preg_replace("/$sPoint?0+$/", "", sprintf("%f", $this->fSize)) : $this->fSize;
+            ? preg_replace("/$sPoint?0+$/", "", sprintf("%f", $this->fSize)) : (string)$this->fSize;
         return preg_replace(["/$sPoint/", "/^(-?)0\./"], ['.', '$1.'], $sSize)
             . ($this->sUnit === null ? '' : $this->sUnit);
     }

tests/ParserTest.php

@@ -279,7 +279,7 @@ public function specificity()
             new Selector('ol li::before', true),
         ], $oDoc->getSelectorsBySpecificity('< 100'));
         self::assertEquals([new Selector('li.green', true)], $oDoc->getSelectorsBySpecificity('11'));
-        self::assertEquals([new Selector('ol li::before', true)], $oDoc->getSelectorsBySpecificity(3));
+        self::assertEquals([new Selector('ol li::before', true)], $oDoc->getSelectorsBySpecificity('3'));
     }
 
     /**