Add support for multiline diff with capture mode.

Author: janbarasek

src/SimpleDiff.php

@@ -19,16 +19,25 @@ public function compare(string $left, string $right, bool $strict = false): Diff
 		$to = explode("\n", $right);
 		$padLength = strlen((string) max(count($from), count($to)));
 		$changedLines = [];
+		$captureBuffer = [];
 
 		for ($i = 0; isset($from[$i]); $i++) {
 			$original = $from[$i] ?? '';
 			$target = $to[$i] ?? '';
 			$lineNumber = str_pad((string) ($i + 1), $padLength, ' ', STR_PAD_LEFT) . '| ';
 			if ($original === $target) {
+				if ($captureBuffer !== []) {
+					foreach ($captureBuffer as $captureType => $captureLines) {
+						foreach ($captureLines as $captureLine) {
+							$return[] = $captureLine;
+						}
+					}
+					$captureBuffer = [];
+				}
 				$return[] = '  ' . $lineNumber . $original;
 			} else {
-				$return[] = '- ' . $lineNumber . $this->prettyRender($original);
-				$return[] = '+ ' . $lineNumber . $this->prettyRender($target);
+				$captureBuffer['-'][] = '- ' . $lineNumber . $this->prettyRender($original);
+				$captureBuffer['+'][] = '+ ' . $lineNumber . $this->prettyRender($target);
 				$changedLines[] = $i + 1;
 			}
 		}