fix import of createContext in context.md (#1279)

Author: 38elements

packages/lit-dev-content/site/docs/v2/data/context.md

@@ -335,7 +335,7 @@ Creates a typed Context object
 **Import**:
 
 ```ts
-import {property} from '@lit-labs/context';
+import {createContext} from '@lit-labs/context';
 ```
 
 **Signature**:

packages/lit-dev-content/site/docs/v3/data/context.md

@@ -333,7 +333,7 @@ Creates a typed Context object
 **Import**:
 
 ```ts
-import {property} from '@lit/context';
+import {createContext} from '@lit/context';
 ```
 
 **Signature**: