Fix search terms containing regex characters

.craftplugin

@@ -1 +1 @@
-{"pluginName":"Extended Search","pluginDescription":"Retrieve additional context for Element searches","pluginVersion":"0.0.2","pluginAuthorName":"Studentenwerk OstNiedersachsen","pluginVendorName":"Studentenwerk OstNiedersachsen","pluginAuthorUrl":"https://stw-on.de","pluginAuthorGithub":"stw-on","codeComments":"yes","pluginComponents":["models","services","variables"],"consolecommandName":"","controllerName":"","cpsectionName":"","elementName":"","fieldName":"","modelName":"","purchasableName":"","recordName":"","serviceName":"","taskName":"","utilityName":"","widgetName":"","apiVersion":"api_version_3_0"}
+{"pluginName":"Extended Search","pluginDescription":"Retrieve additional context for Element searches","pluginVersion":"0.0.3","pluginAuthorName":"Studentenwerk OstNiedersachsen","pluginVendorName":"Studentenwerk OstNiedersachsen","pluginAuthorUrl":"https://stw-on.de","pluginAuthorGithub":"stw-on","codeComments":"yes","pluginComponents":["models","services","variables"],"consolecommandName":"","controllerName":"","cpsectionName":"","elementName":"","fieldName":"","modelName":"","purchasableName":"","recordName":"","serviceName":"","taskName":"","utilityName":"","widgetName":"","apiVersion":"api_version_3_0"}

composer.json

@@ -2,7 +2,7 @@
 	"name": "stw-on/craft-extended-search",
 	"description": "Retrieve additional context for Element searches",
 	"type": "craft-plugin",
-	"version": "2.0.0",
+	"version": "2.0.1",
 	"keywords": [
 		"craft",
 		"cms",

src/services/ExtendedSearchService.php

@@ -144,7 +144,7 @@ protected function getNormalizedValue($value)
 	protected function contextualizeHit($content, $term, $length)
 	{
 		$content = strip_tags($content);
-		$pattern = '/(' . $term . ')/im';
+		$pattern = '/(' . preg_quote($term) . ')/im';
 		$midway = round($length / 2);
 		if (strlen($content) > $length) {
 			// if the hit is after the middle, we need to shorten the text on both sides