Tweaks to "usage" docs page

Move summary of exceptions to the beginning with links to subsections on the same page.
Use instant data preview for exceptions, similar to functions.
Use horizontal rules to separate main sections.

Author: Electronic-Mango

docs/usage.md

@@ -29,6 +29,17 @@ module - `simplejustwatchapi`.
 Examples of parsed responses are in the GitHub repository in
 [`examples/`](https://github.com/Electronic-Mango/simple-justwatch-python-api/tree/main/examples).
 
+---
+
+Each function can raise two exceptions:
+
+ - [`JustWatchHttpError`](#http-errors) - JustWatch API responded with non-`2xx` code.
+ - [`JustWatchApiError`](#api-errors) - JSON response from JustWatch API contains
+    errors.
+
+You can check [Exceptions](API Reference/exceptions.md) page for more details.
+
+---
 
 ## Functions
 
@@ -261,21 +272,15 @@ exact 3-letter code needed there.
 Example function call and its output is in
 [`examples/providers_output.py`](https://github.com/Electronic-Mango/simple-justwatch-python-api/blob/main/examples/providers_output.py).
 
-
+---
 
 ## Error handling
 
-Each function can raise two exceptions:
-
-| Exception                                                                              | Cause |
-|----------------------------------------------------------------------------------------|-------|
-| [`JustWatchHttpError`][simplejustwatchapi.exceptions.JustWatchHttpError]{data-preview} | JustWatch API responded with non-`2xx` code. |
-| [`JustWatchApiError`][simplejustwatchapi.exceptions.JustWatchApiError]{data-preview}   | JSON response from JustWatch API contains errors,<br>even though the API responded with a `2xx` status code. |
-
-You can check [Exceptions](API Reference/exceptions.md) page for more details.
-
 ### HTTP errors
 
+[`JustWatchHttpError`][simplejustwatchapi.exceptions.JustWatchHttpError]{data-preview}
+is raised when JustWatch API responds with non-`2xx` status code.
+
 Non-`2xx` response status codes can happen when trying to use incorrect type for
 parameters, e.g., trying to use a non-numeric string for `count`:
 
@@ -303,6 +308,10 @@ except JustWatchHttpError as e:
 
 ### API errors
 
+[`JustWatchApiError`][simplejustwatchapi.exceptions.JustWatchApiError]{data-preview} is
+raised when JustWatch API **does** respond with `2xx` status code, but the internal JSON
+response contain errors.
+
 API errors can occur for invalid country code:
 ```python
 from simplejustwatchapi import search, JustWatchApiError
@@ -361,6 +370,7 @@ except JustWatchApiError as e:
 These are just examples of internal API errors, which cause [`JustWatchApiError`]
 [simplejustwatchapi.exceptions.JustWatchApiError] exception.
 
+---
 
 ## More complicated examples