minor #8934 Explain why the Web Debug Toolbar is gone (marcelkorpel, javiereguiluz)

This PR was merged into the 4.0 branch.

Discussion
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Explain why the Web Debug Toolbar is gone

When rendering a response using a template, the Web Debug Toolbar is gone, which was confusing to me. Only after searching I found the reason: there is no body element when using this rendering method. It seems logical to me to also explain extending a template to incorporate base.html.twig, so the Toolbar re-appears.

Commits
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b1cf487 Wrap long lines
0c272c3 Reword explanation
1c25c7c Explain why the Web Debug Toolbar is gone

Author: javiereguiluz

page_creation.rst

@@ -262,6 +262,10 @@ to get your *new* lucky number!
 
     http://localhost:8000/lucky/number
 
+Now you may wonder where the Web Debug Toolbar has gone: that's because there is
+no ``</body>`` tag in the current template. You can add the body element yourself,
+or extend ``base.html.twig``, which contains all default HTML elements.
+
 In the :doc:`/templating` article, you'll learn all about Twig: how to loop, render
 other templates and leverage its powerful layout inheritance system.