docs: Syntax highlighting for mkdocs (#984)

* feat:forward context processors variables in context in ISOLATED mode

	provide context_processors_data property to Component to access those variables in Component

* refactor: internalize RequestContext and pass HttpRequest internally

* docs: document HttpRequest and context processors

* docs: use djc_py code blocks for component definitions

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Co-authored-by: Lilian Durey <dureylilian@gmail.com>

docs/templates/reference_signals.md

@@ -12,7 +12,7 @@ the signal is triggered for each component.
 
 Import from django as `django.test.signals.template_rendered`.
 
-```python
+```djc_py
 from django.test.signals import template_rendered
 
 # Setup a callback function