[DOCS] Fix edge n-gram tokenizer nav

Adds a missing float tag to the edge n-gram tokenizer docs. This tag
ensures the edge n-gram tokenizer docs display on the same page.

docs/reference/analysis/tokenizers/edgengram-tokenizer.asciidoc

@@ -105,6 +105,7 @@ Character classes may be any of the following:
     setting this to `+-_` will make the tokenizer treat the plus, minus and
     underscore sign  as part of a token.
 
+[float]
 [[max-gram-limits]]
 === Limitations of the `max_gram` parameter