docs(vrl): add documentation for parse_etld function

.github/actions/spelling/allow.txt

@@ -278,6 +278,7 @@ downsides
 downwardapi
 emoji
 esbuild
+etld
 fakeintake
 fargate
 fibonacci

website/cue/reference/remap/functions/parse_etld.cue

@@ -0,0 +1,66 @@
+package metadata
+
+remap: functions: parse_etld: {
+	category:    "Parse"
+	description: """
+		Parses the [eTLD](\(urls.etld)) from `value` representing domain name.
+		"""
+
+	arguments: [
+		{
+			name:        "value"
+			description: "The domain string."
+			required:    true
+			type: ["string"]
+		},
+		{
+			name: "plus_parts"
+			description: """
+				Can be provided to get additional parts of the domain name. When 1 is passed,
+				eTLD+1 will be returned, which represents a domain registrable by a single
+				organization. Higher numbers will return subdomains.
+				"""
+			required: false
+			type: ["integer"]
+			default: false
+		},
+	]
+	internal_failure_reasons: []
+	return: types: ["object"]
+
+	examples: [
+		{
+			title: "Parse eTLD"
+			source: #"""
+				parse_etld!("sub.sussex.ac.uk")
+				"""#
+			return: {
+				etld:         "ac.uk"
+				etld_plus:    "ac.uk"
+				known_suffix: true
+			}
+		},
+		{
+			title: "Parse eTLD+1"
+			source: #"""
+				parse_etld!("sub.sussex.ac.uk", plus_parts: 1)
+				"""#
+			return: {
+				etld:         "ac.uk"
+				etld_plus:    "sussex.ac.uk"
+				known_suffix: true
+			}
+		},
+		{
+			title: "Parse eTLD with unknown suffix"
+			source: #"""
+				parse_etld!("vector.acmecorp")
+				"""#
+			return: {
+				etld:         "acmecorp"
+				etld_plus:    "acmecorp"
+				known_suffix: false
+			}
+		},
+	]
+}

website/cue/reference/urls.cue

@@ -186,6 +186,7 @@ urls: {
 	endler_dev:                                 "https://endler.dev/"
 	enrichment_tables_concept:                  "/docs/reference/glossary/#enrichment-tables"
 	eof:                                        "\(wikipedia)/wiki/End-of-file#EOF_character"
+	etld:                                       "https://developer.mozilla.org/en-US/docs/Glossary/eTLD"
 	etsy:                                       "https://www.etsy.com"
 	event_proto:                                "\(vector_repo)/blob/master/lib/vector-core/proto/event.proto"
 	eventstoredb_stats_client:                  "https://developers.eventstore.com/server/v21.2/docs/diagnostics/stats.html"