docs: Add info and resolution for missing xcb plugin error

Signed-off-by: Sietze van Buuren <[email protected]>

docs/installation.md

@@ -28,4 +28,23 @@ pip install /path/to/mlpyqtgraph
 ```
 
 Now, mpyqtgraph can be used whenever the appropriate virtual environment has
-been activated.
+been activated e.g., by trying the [minimal example](https://github.com/swvanbuuren/mlpyqtgraph/blob/master/examples/minimal.py):
+
+```bash
+python examples/minimal.py
+```
+
+!!! info
+
+    If you receive an error message similar to the following:
+
+    ```plaintext
+    Could not load the Qt platform plugin "xcb" in "" even though it was found."
+    ```
+
+    Then, you might need to install additional dependencies. On a Debian-based 
+    system, this is accomplished with:
+
+    ```bash
+    sudo apt install -y libxcb-cursor-dev
+    ```

mkdocs.yml

@@ -9,6 +9,7 @@ theme:
   - navigation.sections
   - navigation.tabs
   - navigation.indexes
+  - content.code.annotate
   - content.code.copy
 
 plugins:
@@ -21,6 +22,9 @@ plugins:
 
 markdown_extensions:
   - attr_list
+  - md_in_html
+  - admonition
+  - pymdownx.details
   - pymdownx.emoji:
       emoji_index: !!python/name:material.extensions.emoji.twemoji
       emoji_generator: !!python/name:material.extensions.emoji.to_svg
@@ -29,7 +33,8 @@ markdown_extensions:
       line_spans: __span
       pygments_lang_class: true
   - pymdownx.inlinehilite
-  - pymdownx.snippets
+  - pymdownx.snippets:
+      url_download: true
   - pymdownx.superfences