Add docs code testing & documentation syntax changes (#196)

- Creates testing files `md_testing.py` and `md_testing.js` for testing
python and nodejs code in markdown files in the documentation
This listens for HTML tags as well: `<!--[language] code code
code...-->` will create a set-up file to create some mock tables or to
fulfill some assumptions in the documentation.
- Creates a github action workflow that triggers every push/pr to
`docs/**`
- Modifies documentation so tests run (mostly indentation, some small
syntax errors and some missing imports)

A list of excluded files that we need to take a closer look at later on:
```javascript
const excludedFiles = [
  "../src/fts.md",
  "../src/embedding.md",
  "../src/examples/serverless_lancedb_with_s3_and_lambda.md",
  "../src/examples/serverless_qa_bot_with_modal_and_langchain.md",
  "../src/examples/youtube_transcript_bot_with_nodejs.md",
];
```
Many of them can't be done because we need the OpenAI API key :(.
`fts.md` has some issues with the library, I believe this is still
experimental?

Closes #170

---------

Co-authored-by: Will Jones <willjones127@gmail.com>

docs/src/sql.md

@@ -15,11 +15,35 @@ Currently, Lance supports a growing list of expressions.
 * ``regexp_match(column, pattern)``
 
 For example, the following filter string is acceptable:
+<!-- Setup Code
+```python 
+import lancedb
+import numpy as np
+uri = "data/sample-lancedb"
+db = lancedb.connect(uri)
 
+data = [{"vector": row, "item": f"item {i}"}
+     for i, row in enumerate(np.random.random((10_000, 2)).astype('int'))]
+
+tbl = db.create_table("my_vectors", data=data)
+```
+-->
+<!-- Setup Code
+```javascript 
+const vectordb = require('vectordb')
+const db = await vectordb.connect('data/sample-lancedb')
+
+let data = []
+for (let i = 0; i < 10_000; i++) {
+     data.push({vector: Array(1536).fill(i), id: `${i}`, content: "", longId: `${i}`},)
+}
+const tbl = await db.createTable('my_vectors', data)
+```
+-->
 === "Python"
 
     ```python
-    tbl.search([100, 102])
+    tbl.search([100, 102]) \
        .where("""(
         (label IN [10, 20])
         AND