fix typo in synonym graph filter docs

docs/reference/analysis/tokenfilters/synonym-graph-tokenfilter.asciidoc

@@ -174,7 +174,8 @@ PUT /test_index
 Using `synonyms_path` to define WordNet synonyms in a file is supported
 as well.
 
-=== Parsing synonym files
+[float]
+==== Parsing synonym files
 
 Elasticsearch will use the token filters preceding the synonym filter
 in a tokenizer chain to parse the entries in a synonym file.  So, for example, if a
@@ -186,7 +187,7 @@ parsing synonyms, e.g. `asciifolding` will only produce the folded version of th
 token.  Others, e.g. `multiplexer`, `word_delimiter_graph` or `ngram` will throw an
 error.
 
-WARNING:The synonym rules should not contain words that are removed by
+WARNING: The synonym rules should not contain words that are removed by
 a filter that appears after in the chain (a `stop` filter for instance).
 Removing a term from a synonym rule breaks the matching at query time.