fixups after reviewer comments

use ".<filetype>" instead of "<filetype>" when echoing their deletion.
add comment explaining why wildcard deletion of files is not used.

init.sh

@@ -111,14 +111,15 @@ echo "Copying contents to the installation directory..."
 cp -R "$temp_directory"/sp-files/* "$temp_directory"/sp-files/.??* "$install_directory"
 
 # Delete files with unpreferred filetype in the installation directory
+# No wildcard delete to avoid data loss if user Git-inits in dir with pre-existing files
 if [ -z "${default_filetype_choice:-}" ]; then
     echo "Default filetype not defined, so proceed with deleting unpreferred filetype."
     if [ "$file_type" = 'md' ]; then
-        echo "Deleting rst files..."
+        echo "Deleting .rst files..."
         rm "$install_directory"/doc-cheat-sheet.rst
         rm "$install_directory"/index.rst
     else
-        echo "Deleting md files..."
+        echo "Deleting .md files..."
         rm "$install_directory"/doc-cheat-sheet-myst.md
         rm "$install_directory"/index.md
     fi