Fix typo on analyze.asciidoc (#19354)

docs/reference/indices/analyze.asciidoc

@@ -70,7 +70,7 @@ can also be provided to use a different analyzer:
 curl -XGET 'localhost:9200/test/_analyze' -d '
 {
   "analyzer" : "whitespace",
-  "text : "this is a test"
+  "text" : "this is a test"
 }'
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