Conserve ending newlines in story string template

public/script.js

@@ -1638,6 +1638,15 @@ function scrollChatToBottom() {
     }
 }
 
+/**
+ * Substitutes {{macro}} parameters in a string.
+ * @param {string} content - The string to substitute parameters in.
+ * @param {*} _name1 - The name of the user. Uses global name1 if not provided.
+ * @param {*} _name2 - The name of the character. Uses global name2 if not provided.
+ * @param {*} _original - The original message for {{original}} substitution.
+ * @param {*} _group - The group members list for {{group}} substitution.
+ * @returns {string} The string with substituted parameters.
+ */
 function substituteParams(content, _name1, _name2, _original, _group) {
     _name1 = _name1 ?? name1;
     _name2 = _name2 ?? name2;