docs(v4): add "Theme installation options" section in migration guide. (#555)

Author: igor-baiborodine

v4-migration-guide.md

@@ -3,6 +3,18 @@
 **IMPORTANT** The Hugo version was bumped to `v0.109.0 extended`. Therefore, you should upgrade Hugo in your local
 development environment and, if necessary, in the corresponding deployment configuration file.
 
+### Theme Installation Options
+
+Depending on your chosen theme installation option, update the theme property in the `config.toml` file as follows:
+
+```toml
+# Option 1 (recommended) : adding the theme as a Hugo module
+theme = "github.com/Lednerb/bilberry-hugo-theme/v4"
+
+# Options 2 and 3: cloning/copying the theme files
+theme = "bilberry-hugo-theme/v4"
+```
+
 ### Top Navigation Bar
 
 1. Remove completely the `excludeFromTopNav` variable from all content files in the `content/page` folder.

v4/exampleSite/config.toml

@@ -4,7 +4,7 @@ baseURL = "https://example.com/"
 # Option 1 (recommended): adding the theme as a Hugo module
 theme = "github.com/Lednerb/bilberry-hugo-theme/v4"
 
-# Option 2: cloning/copying the theme files
+# Options 2 and 3: cloning/copying the theme files
 # theme = "bilberry-hugo-theme/v4"
 
 # Generate the robots.txt file for SEO
@@ -20,7 +20,7 @@ googleAnalytics = ""
 disqusShortname = ""
 
 [params]
-  # Custom CSS / JS modules that will be imported by the template.
+  # Custom CSS/JS modules that will be imported by the template.
   # Files are relative to the static/ directory or a URL.
   # Files are imported in the order they appear here, after
   # theme.css and theme.js, respectively.