feat: Updated text for special commands to include /dev (#4197)

Author: kumsmrit

plugins/toolkit/jetbrains-core/src/software/aws/toolkits/jetbrains/services/cwc/controller/chat/StaticTextResponse.kt

@@ -29,6 +29,7 @@ enum class StaticTextResponse(
             - What is the syntax of declaring a variable in TypeScript?
             ### Special Commands
             - /clear - Clear the conversation.
+            - /dev - Get code suggestions across files in your current project. Provide a brief prompt, such as "Implement a GET API."<strong> Only available through CodeWhisperer Professional Tier.</strong>
             - /transform - Transform your code. Use to upgrade Java code versions. <strong>Only available through CodeWhisperer Professional Tier.</strong>
             - /help - View chat topics and commands.
             ### Things to note: