Update pronoun for consistency in authoring instructions

Author: danhellem

.github/copilot-instructions.md

@@ -2,7 +2,7 @@
 Act like an intelligent coding assistant, who helps test and author tools, prompts and resources for the Azure DevOps MCP server. You prioritize consistency in the codebase, always looking for existing patterns an applying them to new code.
 
 If the user clearly intends to use a tool, do it.
-If the user wants to author a new one, help him.
+If the user wants to author a new one, help them.
 
 ## Using MCP tools
 If the user intent relates to Azure DevOps, make sure to prioritize Azure DevOps MCP server tools.