Add prefix: jecfa (#1255)

This pull request addresses part of
#1247 by introducing
a new prefix `jecfa`.

Since the URL for individual entries does not use the JECFA Number, but
rather an unrelated number, it is curated without a `uri_format` field.

---------

Co-authored-by: Mufaddal Naguthanawala <[email protected]>
Co-authored-by: Ben Gyori <[email protected]>

src/bioregistry/data/bioregistry.json

@@ -59290,6 +59290,43 @@
       "uri_format": "http://nikkajiweb.jst.go.jp/nikkaji_web/pages/top_e.jsp?CONTENT=syosai&SN=$1"
     }
   },
+  "jecfa": {
+    "contact": {
+      "email": "[email protected]",
+      "name": "Kim Petersen"
+    },
+    "contributor": {
+      "email": "[email protected]",
+      "github": "nagutm",
+      "name": "Mufaddal Naguthanawala",
+      "orcid": "0009-0009-5240-7463"
+    },
+    "description": "JECFA provides identifiers for flavors, food additives, contaminants, toxicants, and veterinary drugs. Each entry includes chemical details, acceptable or tolerable intake limits, and links to related reports and monographs.",
+    "example": "2116",
+    "github_request_issue": 1247,
+    "homepage": "https://apps.who.int/food-additives-contaminants-jecfa-database",
+    "mappings": {
+      "wikidata": "P9557"
+    },
+    "name": "Joint FAO/WHO Expert Committee on Food Additives",
+    "pattern": "^\\d+$",
+    "reviewer": {
+      "email": "[email protected]",
+      "github": "bgyori",
+      "name": "Benjamin M. Gyori",
+      "orcid": "0000-0001-9439-5346"
+    },
+    "wikidata": {
+      "description": "identifier for food additives assigned by Joint FAO/WHO Expert Committee on Food Additives",
+      "example": [
+        "1",
+        "1851"
+      ],
+      "name": "JECFA number",
+      "pattern": "^\\d+$",
+      "prefix": "P9557"
+    }
+  },
   "jgi.proposal": {
     "contact": {
       "email": "[email protected]",