fix: Search plugin: matched text is replaced with search text (#1298)

* Fix search plugin will replace matching text

* Fix bug that will replace a unexpected text

* Fix bug that will replace a unexpected text

* Optimized

Co-authored-by: 沈唁 <52o@qq52o.cn>

src/plugins/search/search.js

@@ -170,7 +170,10 @@ export function search(query) {
             '...' +
             escapeHtml(postContent)
               .substring(start, end)
-              .replace(regEx, `<em class="search-keyword">${keyword}</em>`) +
+              .replace(
+                regEx,
+                word => `<em class="search-keyword">${word}</em>`
+              ) +
             '...';
 
           resultStr += matchContent;