diff --git a/doc/mkdocs/mkdocs.yml b/doc/mkdocs/mkdocs.yml
index d716c2d9a..17fbb4624 100644
--- a/doc/mkdocs/mkdocs.yml
+++ b/doc/mkdocs/mkdocs.yml
@@ -280,7 +280,7 @@ markdown_extensions:
 
 plugins:
     - search:
-        separator: '[\s\-\.]'
+        separator: '[\s\-\._]'
         lang: en
     - minify:
         minify_html: true