Update radial_tissue_term description

Co-authored-by: Hannes Schmidt <[email protected]>

Author: idazucchi

json_schema/type/biomaterial/specimen_from_organism.json

@@ -66,7 +66,7 @@
             "user_friendly": "Organ part"
         },
         "radial_tissue_term": {
-            "description": "Layer(s) of the gut that was sampled.",
+            "description": "Layer(s) of the gut that was/were sampled.",
             "example": "EPI; LP; MUSC; SUB; MLN",
             "type": "array",
             "items": {