fix hard-to-read mermaid chart in ev example

docs/content/examples/example_electric_vehicle_premise.ipynb

@@ -318,12 +318,12 @@
     "\n",
     "```{mermaid}\n",
     "flowchart LR\n",
-    "    glider_production(glider production):::ei-->|0-2 years prior|ev_production\n",
-    "    powertrain_production(powertrain production):::ei-->|1 year prior|ev_production\n",
-    "    battery_production(battery production):::ei-->|1 year prior|ev_production\n",
-    "    ev_production(ev production):::fg-->|0-3 months prior|driving\n",
+    "    glider_production(glider production):::ei-->|\"0-2 years prior \\n  \"|ev_production\n",
+    "    powertrain_production(powertrain production):::ei-->|\"1 year prior \\n  \"|ev_production\n",
+    "    battery_production(battery production):::ei-->|\"  \\n 1 year prior\"|ev_production\n",
+    "    ev_production(ev production):::fg-->|\"0-3 months prior \\n  \"|driving\n",
     "    electricity_generation(electricity generation):::ei-->|uniformly distributed \\n over lifetime|driving\n",
-    "    driving(driving):::fg-->|after ev lifetime|used_ev\n",
+    "    driving(driving):::fg-->|\"after ev lifetime \\n  \"|used_ev\n",
     "    used_ev(used ev):::fg-->|3 months after \\n ev lifetime|glider_eol(glider eol):::ei\n",
     "    used_ev-->|3 months after \\n ev lifetime|powertrain_eol(powertrain eol):::ei\n",
     "    used_ev-->|3 months after \\n ev lifetime|battery_eol(battery eol):::ei\n",