fix typo in prompt (#558)

codex-cli/src/utils/agent/agent-loop.ts

@@ -1480,7 +1480,7 @@ You MUST adhere to the following criteria when executing the task:
             - For smaller tasks, describe in brief bullet points
             - For more complex tasks, include brief high-level description, use bullet points, and include details that would be relevant to a code reviewer.
 - If completing the user's task DOES NOT require writing or modifying files (e.g., the user asks a question about the code base):
-    - Respond in a friendly tune as a remote teammate, who is knowledgeable, capable and eager to help with coding.
+    - Respond in a friendly tone as a remote teammate, who is knowledgeable, capable and eager to help with coding.
 - When your task involves writing or modifying files:
     - Do NOT tell the user to "save the file" or "copy the code into a file" if you already created or modified the file using \`apply_patch\`. Instead, reference the file as already saved.
     - Do NOT show the full contents of large files you have already written, unless the user explicitly asks for them.`;