Add empty parens to docs

docs/patterns/cli.mdx

@@ -66,7 +66,7 @@ from fastmcp import FastMCP
 
 mcp = FastMCP("MyServer")
 
-@mcp.tool
+@mcp.tool()
 def hello(name: str) -> str:
     return f"Hello, {name}!"
 

docs/patterns/decorating-methods.mdx

@@ -28,7 +28,7 @@ from fastmcp import FastMCP
 mcp = FastMCP()
 
 class MyClass:
-    @mcp.tool  # This won't work correctly
+@mcp.tool()  # This won't work correctly
     def add(self, x, y):
         return x + y
     
@@ -83,7 +83,7 @@ mcp = FastMCP()
 
 class MyClass:
     @classmethod
-    @mcp.tool  # This won't work correctly
+@mcp.tool()  # This won't work correctly
     def from_string(cls, s):
         return cls(s)
 ```
@@ -122,7 +122,7 @@ mcp = FastMCP()
 
 class MyClass:
     @staticmethod
-    @mcp.tool  # This works!
+@mcp.tool()  # This works!
     def utility(x, y):
         return x + y
     

docs/patterns/http-requests.mdx

@@ -25,7 +25,7 @@ from starlette.requests import Request
 
 mcp = FastMCP(name="HTTP Request Demo")
 
-@mcp.tool
+@mcp.tool()
 async def user_agent_info() -> dict:
     """Return information about the user agent."""
     # Get the HTTP request
@@ -58,7 +58,7 @@ from fastmcp.server.dependencies import get_http_headers
 
 mcp = FastMCP(name="Headers Demo")
 
-@mcp.tool
+@mcp.tool()
 async def safe_header_info() -> dict:
     """Safely get header information without raising errors."""
     # Get headers (returns empty dict if no request context)

docs/patterns/testing.mdx

@@ -22,7 +22,7 @@ from fastmcp import FastMCP, Client
 def mcp_server():
     server = FastMCP("TestServer")
     
-    @server.tool
+@server.tool()
     def greet(name: str) -> str:
         return f"Hello, {name}!"