update get_htmo_text.md

data/2.python中阶/3.网络爬虫/4.lxml/get_html_text.md

@@ -94,6 +94,6 @@ def fetch_text(html):
 ```python
 def fetch_text(html):
     html = etree.HTML(html)
-    result = html.xpath("/text()")
+    result = html.xpath("//get_text()")
     return result
 ```