Update properties.json

Author: lzehl

vocab/properties.json

@@ -12012,7 +12012,7 @@
     "label": "Intermediate diameter",
     "labelPlural": "Intermediate diameters",
     "name": "intermediateDiameter",
-    "namePlural": "intermediateDiameter",
+    "namePlural": "intermediateDiameters",
     "usedIn": {
       "latest": [
         "https://openminds.om-i.org/types/Ellipsoid"