Fix documentation build (swiftlang#9980)

* Fix a documentation build failure caused by missing _ underscore in footnote citation.

* Get archive/LangRef.html building again. I'm not sure this is the most desirable way to address the failure to locate archive/LangRef.html but I confirmed this causes the desired _build/html/archive/LangRef.html to be created when making docs.

Author: danielpunkass

docs/conf.py

@@ -29,7 +29,7 @@
 extensions = ['sphinx.ext.intersphinx', 'sphinx.ext.todo']
 
 # Add any paths that contain templates here, relative to this directory.
-templates_path = ['_templates']
+templates_path = ['_templates', 'archive']
 
 # The suffix of source filenames.
 source_suffix = '.rst'
@@ -146,7 +146,7 @@
 
 # Additional templates that should be rendered to pages, maps page names to
 # template names.
-html_additional_pages = {'LangRef': 'archive/LangRef.html'}
+html_additional_pages = {'archive/LangRef': 'LangRef.html'}
 
 # If false, no module index is generated.
 # html_domain_indices = True

docs/proposals/InitializerInheritance.rst

@@ -135,7 +135,7 @@ doing so is safe.
 Complete object initializers
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Introduce the notion of a complete object initializer, which is
-written as an initializer with ``Self`` as its return type [#], e.g.::
+written as an initializer with ``Self`` as its return type [#]_, e.g.::
 
   init() -> Self {
     // ...