More tidying worker docs

docs/usage/webworker.md

@@ -5,18 +5,22 @@
 This document includes an example demonstrating how to use Pyodide to execute
 Python scripts asynchronously in a web worker.
 
-Let's start with [the definition][worker api].
+Let's start with [the definition of a worker][worker api].
 
 > A worker is an object created using a constructor (e.g. [Worker()][worker constructor])
 > that runs a named JavaScript file — this file contains the code
 > that will run in the worker thread; workers run in another global context that
 > is different from the current window.
 
-A lot of Python code does long running synchronous computations. Running them in
-the main thread will block the UI. Using a web worker is advantageous because
-the Python code runs in a separate thread from your UI and does not impact your
+A lot of Python programs do long-running synchronous computations. Running them
+in the main thread blocks the UI. Using a web worker is advantageous because the
+Python code runs in a separate thread from your UI and does not impact your
 application's responsiveness.
 
+On the other hand, since workers run in a separate global context, you cannot
+directly share globals between a worker and the main thread. In particular, a
+worker cannot directly manipulate the DOM.
+
 ## Detailed example
 
 In this example process we will have three parties involved:
@@ -149,11 +153,3 @@ export function asyncRun(script, context) {
 [worker api]: https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API
 [worker constructor]: https://developer.mozilla.org/en-US/docs/Web/API/Worker/Worker
 
-## Caveats
-
-There are some limitations, however. Pyodide does not support sharing the Python
-interpreter and packages between multiple workers or with your main thread.
-Since workers run in a separate global context distinct from the main thread,
-you cannot directly share globals between a worker and your main thread. In
-particular, the worker cannot directly manipulate the DOM. Finally, although the
-worker is separate from your main thread, the worker is itself single threaded.