wip: make the python API reference a bit nicer (#162)

Adds:

* Make `mkdocstrings` aware we are using numpy-style docstrings
* Fixes broken link on `index.md` to Python API docs (and added link to
node ones)
* Added examples to various classes.
* Added doctest to verify examples work.

docs/src/python/python.md

@@ -6,9 +6,38 @@
 pip install lancedb
 ```
 
-## ::: lancedb
-## ::: lancedb.db
-## ::: lancedb.table
-## ::: lancedb.query
-## ::: lancedb.embeddings
-## ::: lancedb.context
+## Connection
+
+::: lancedb.connect
+
+::: lancedb.LanceDBConnection
+
+## Table
+
+::: lancedb.table.LanceTable
+
+## Querying
+
+::: lancedb.query.LanceQueryBuilder
+
+::: lancedb.query.LanceFtsQueryBuilder
+
+## Embeddings
+
+::: lancedb.embeddings.with_embeddings
+
+::: lancedb.embeddings.EmbeddingFunction
+
+## Context
+
+::: lancedb.context.contextualize
+
+::: lancedb.context.Contextualizer
+
+## Full text search
+
+::: lancedb.fts.create_index
+
+::: lancedb.fts.populate_index
+
+::: lancedb.fts.search_index