Add image-editing feature documentation to the !bai usage command and adjust texts a bit

src/strings/help/usage.rs

@@ -3,5 +3,5 @@ pub fn heading() -> &'static str {
 }
 
 pub fn intro() -> &'static str {
-    "The bot can perform various tasks, such as 💬 Text Generation, 🗣️ Text-to-Speech, 🦻 Speech-to-Text, 🖌️ Image Creation, and more."
+    "The bot can perform various tasks, such as 💬 Text Generation, 🗣️ Text-to-Speech, 🦻 Speech-to-Text, 🖌️ Image Generation, and more."
 }