docs: fix typo in en/browserslist.mdx (#5280)

Author: Timeless0911

website/docs/en/guide/advanced/browserslist.mdx

@@ -32,7 +32,7 @@ Rsbuild will set different default values of Browserslist according to [output.t
 
 ### Web target
 
-If [output.target`is`web`, Rsbuild will use the following Browserslist by default:
+If `output.target` is `web`, Rsbuild will use the following Browserslist by default:
 
 ```yaml title=".browserslistrc"
 chrome >= 87