Link every page into the navigation

~870 pages weren't reachable from any toctree, so they had no sidebar
context and only showed up via search or direct links:

- python/archive/index was generated before ~370 pages landed in the
  directory; regenerate its entries from the directory contents.
- psf/about/index wrapped its toctree in a ```plain fence, so none of
  its seven pages were linked.
- Ten directories (python/conferences/, PyDevSummaries/, ...) had
  subsections but no index page, which cut off everything below them,
  including all of EuroPython, PyCon and the regional conferences.
  Add generated index pages and list them from their parents.
- A few section indexes were missing a subdirectory entry.

Author: JacobCoffee

jython/community/index.md

@@ -21,6 +21,7 @@ The people and events around Jython. This section lists who uses Jython, who bui
 :hidden:
 :maxdepth: 1
 
+SummerOfCode/index
 BofTopics
 JythonEditors
 JythonSprint

jython/newsletter/JythonMonthly/Interviews/index.md

@@ -0,0 +1,8 @@
+# Interviews
+
+```{toctree}
+:maxdepth: 1
+
+August2008/index
+July2008/index
+```

jython/newsletter/JythonMonthly/index.md

@@ -4,6 +4,7 @@
 :maxdepth: 1
 
 Articles/index
+Interviews/index
 Newsletters/index
 Articles
 Interviews

psf/about/index.md

@@ -18,8 +18,7 @@ This section covers the foundation-level basics: what the PSF stands for, how it
 - [Wiki Instructions](WikiInstructions) -- How to edit pages, create links, and use the wiki
 - [Reference Materials](reference) -- Recommended reading for nonprofit management
 
-```plain
-{toctree}
+```{toctree}
 :hidden:
 :maxdepth: 1