[DOCS] Remove unneeded filter from common grams analyze ex (#48748)

Author: jrodewig

docs/reference/analysis/tokenfilters/common-grams-tokenfilter.asciidoc

@@ -30,7 +30,7 @@ GET /_analyze
 {
   "tokenizer" : "whitespace",
   "filter" : [
-    "common_grams", {
+    {
       "type": "common_grams",
       "common_words": ["is", "the"]
     }