Improve diff highlighting to understand multiple files

[chriskuehl]

Here's an example diff with several different file types: https://i.fluffy.cc/4GH3s8gk5kvk6LZNLjgHSsHdnc7PQDsR.html

The autodetection often fails completely (like in the case above) or detects the wrong or a random file type, making the rest of the diff look bad.

It'd be cool to split the diff into chunks and highlight them individually. I'm thinking for the example above, these chunks would make sense:

diff --git a/ocfweb/middleware/errors.py b/ocfweb/middleware/errors.py
index e39319e..26dd093 100644
--- a/ocfweb/middleware/errors.py
+++ b/ocfweb/middleware/errors.py
@@ -15,10 +15,6 @@ class OcflibErrorMiddleware:

         if isinstance(exception, ResponseException):
             return exception.response
 
-        # maybe it's a real exception?
-        if settings.DEBUG or settings.TESTING:
-            return
-
         if isinstance(exception, Http404):
             # we don't care about reporting 404 errors
             return

@@ -54,6 +50,10 @@ class OcflibErrorMiddleware:

             ))
         except Exception as ex:
             print(ex)  # just in case it errors again here
+            if blah:
+                do_foo(
+                    x, y, z,
+                )
             send_problem_report(dedent(
                 """\
                 An exception occured in ocfweb, but we errored trying to report it:

diff --git a/ocfweb/static/js/site.js b/ocfweb/static/js/site.js
index 4e48734..112e029 100644
--- a/ocfweb/static/js/site.js
+++ b/ocfweb/static/js/site.js
@@ -3,16 +3,19 @@ $(document).ready(function() {

     var resizeTimeout;
     var updateFooterHeight = function() {
         var height = $('.ocf-footer').outerHeight();
-        $('body').css('margin-bottom', height);
+            $('body').css('margin-bottom', height);
     };
 
     $(window).resize(function() {
         clearTimeout(resizeTimeout);
-        setTimeout(updateFooterHeight, 10);
     });
 
     updateFooterHeight();
 
+    $(document).thing(function() {
+        return 'lol nope';
+    });
+
     // Close dropdown menu if clicked/tapped outside of
     $(document).click(function(event) {
         var menuOpen = $(".navbar-collapse").hasClass("in");

diff --git a/tox.ini b/tox.ini
index 9553550..4244304 100644
--- a/tox.ini
+++ b/tox.ini
@@ -3,6 +3,10 @@ max-line-length = 119

 # flake8 complains about 'redefinition' of imported pytest fixtures
 ignore = F811
 
+[some-new-section]
+# lol
+foo = blah
+
 [pep8]
 # autopep8 will rewrite lines to be shorter, even though we raised the length
 ignore = E501

Understanding diffs is a bit hard, but supporting the git diff format and maybe diff -u would be a good start.