Update mercure.rst

Co-authored-by: Oskar Stark <[email protected]>

Author: dunglas

mercure.rst

@@ -78,7 +78,7 @@ On Windows run:
 
 .. code-block:: terminal
 
-    $envSERVER_NAME=':3000'; $env:MERCURE_PUBLISHER_JWT_KEY='!ChangeMe!'; $env:MERCURE_SUBSCRIBER_JWT_KEY='!ChangeMe!'; .\mercure.exe run -config Caddyfile.dev
+    $env:SERVER_NAME=':3000'; $env:MERCURE_PUBLISHER_JWT_KEY='!ChangeMe!'; $env:MERCURE_SUBSCRIBER_JWT_KEY='!ChangeMe!'; .\mercure.exe run -config Caddyfile.dev
 
 .. note::