chore: update comments for configuration options baseurl and url

Avoid newbies from misusing these two options

Author: cotes2020

_config.yml

@@ -3,10 +3,6 @@
 # Import the theme
 theme: jekyll-theme-chirpy
 
-# Change the following value to '/PROJECT_NAME' ONLY IF your site type is GitHub Pages Project sites
-# and doesn't have a custom domain.
-baseurl: ""
-
 # The language of the webpage › http://www.lingoes.net/en/translator/langcode.htm
 # If it has the same name as one of the files in folder `_data/locales`, the layout language will also be changed,
 # otherwise, the layout language will use the default value of 'en'.
@@ -25,7 +21,8 @@ tagline: A text-focused Jekyll theme # it will display as the sub-title
 description: >- # used by seo meta and the atom feed
   A minimal, responsive and feature-rich Jekyll theme for technical writing.
 
-# fill in the protocol & hostname for your site, e.g., 'https://username.github.io'
+# Fill in the protocol & hostname for your site.
+# e.g. 'https://username.github.io', note that it does not end with a '/'.
 url: ""
 
 github:
@@ -114,6 +111,9 @@ pwa:
 
 paginate: 10
 
+# The base URL of your site
+baseurl: ""
+
 # ------------ The following options are not recommended to be modified ------------------
 
 kramdown: