docs: Update batch_run import in intro tutorial

Author: EwoutH

docs/overview.md

@@ -103,7 +103,7 @@ To batch-run the model while varying, for example, the n_agents parameter, you'd
 import mesa
 
 parameters = {"n_agents": range(1, 20)}
-mesa.batch_run(
+mesa.batchrunner.batch_run(
     MyModel,
     parameters,
     max_steps=10,

docs/tutorials/intro_tutorial.ipynb

@@ -1166,7 +1166,7 @@
    "source": [
     "params = {\"width\": 10, \"height\": 10, \"N\": range(5, 100, 5)}\n",
     "\n",
-    "results = mesa.batch_run(\n",
+    "results = batch_run(\n",
     "    MoneyModel,\n",
     "    parameters=params,\n",
     "    iterations=7,\n",
@@ -1315,7 +1315,7 @@
    "source": [
     "params = {\"width\": 10, \"height\": 10, \"N\": [5, 10, 20, 40, 80]}\n",
     "\n",
-    "results_5s = mesa.batch_run(\n",
+    "results_5s = batch_run(\n",
     "    MoneyModel,\n",
     "    parameters=params,\n",
     "    iterations=100,\n",