fixed the filtering error in chromadb (#1621)

Fixed two small bugs (as reported in issue #1619 ) in the filtering by
metadata for `chroma` databases :
- ```langchain.vectorstores.chroma.similarity_search``` takes a
```filter``` input parameter but do not forward it to
```langchain.vectorstores.chroma.similarity_search_with_score```
- ```langchain.vectorstores.chroma.similarity_search_by_vector```
doesn't take this parameter in input, although it could be very useful,
without any additional complexity - and it would thus be coherent with
the syntax of the two other functions.

Co-authored-by: Davis Chase <130488702+dev2049@users.noreply.github.com>

langchain/vectorstores/chroma.py

@@ -190,8 +190,9 @@ class Chroma(VectorStore):
     ) -> List[Document]:
         """Return docs most similar to embedding vector.
         Args:
-            embedding: Embedding to look up documents similar to.
-            k: Number of Documents to return. Defaults to 4.
+            embedding (str): Embedding to look up documents similar to.
+            k (int): Number of Documents to return. Defaults to 4.
+            filter (Optional[Dict[str, str]]): Filter by metadata. Defaults to None.
         Returns:
             List of Documents most similar to the query vector.
         """