support and demonstrate the use of footnotes (#141)

guide.tcg

@@ -452,6 +452,22 @@ The result looks like this:
 int i = 42;
 ```
 
+## Footnotes {#sec:footnotes}
+
+```md
+You can use a footnote[^footnote-example] to provide additional details about something
+out of the way, at the bottom of the page.
+
+[^footnote-example]: See @sec:footnotes for more information about footnotes.
+```
+
+You can use a footnote[^footnote-example] to provide additional details about something
+out of the way, at the bottom of the page. The footnotes will be automatically numbered.[^footnote-numbering]
+
+[^footnote-example]: See @sec:footnotes for more information about footnotes.
+
+[^footnote-numbering]: Like this.
+
 ## Cross-References {#sec:cross-references}
 
 In general, sections, tables, figures, and equations can be referenced using the `@` symbol. These cross-references do not show up in the GitHub markdown, but will appear in the final document.
@@ -1092,9 +1108,10 @@ documents in Markdown:
     2.  Release another release candidate marked rc.2, rc.3, etc.
 6.  When the document is approved for public review, send out the release candidate that got
     approved.
-7.  When it comes time for final publication, release just 1.23.5. This will trigger a render
-    of a "Final" styled document. Note that according to the rules of semver, 1.23.5 is higher
-    than 1.23.5-rc.1.
+7.  When it comes time for final publication, release just 1.23.5.[^semver-ordering] This will trigger a render
+    of a "Final" styled document. 
+
+[^semver-ordering]: Note that according to the rules of semver, 1.23.5 is higher than 1.23.5-rc.1.
 
 ::: Note :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
 If the spec is not rendered as part of a release, it will always be

template/tcg.tex

@@ -45,9 +45,10 @@
 %%
 
 % Options for packages loaded elsewhere
-\PassOptionsToPackage{unicode$for(hyperrefoptions)$,$hyperrefoptions$$endfor$}{hyperref}
+\PassOptionsToPackage{unicode,hyperfootnotes=false}{hyperref}
 \PassOptionsToPackage{hyphens}{url}
 \PassOptionsToPackage{dvipsnames,svgnames*,x11names*,table}{xcolor}
+\PassOptionsToPackage{perpage}{footmisc}
 
 \documentclass[
   paper=letter,
@@ -675,6 +676,8 @@
     \SetWatermarkText{\includegraphics[width=8.5in, height=11in]{/resources/img/draft.pdf}}
 }
 
+\usepackage{footnotebackref}
+
 \begin{document}
 
 %%