Add optional woff2 versions of FiraSans.

For browsers that support woff2 (most modern ones:
https://caniuse.com/woff2), this offers a reduction in download size
for these two fonts from 362k to 257k (32% reduction). It decreases the
total page size for `struct.String.html` (counting all subresources) by
about 2.5%.

If this is interesting, I'm happy to apply the same treatment to the
other fonts, but these two are the biggest.

3 files changed, 6 insertions, 2 deletions

diff --git a/src/librustdoc/html/static/FiraSans-Medium.woff2 b/src/librustdoc/html/static/FiraSans-Medium.woff2
new file mode 100644
index 00000000000..7a1e5fc548e
--- /dev/null
+++ b/src/librustdoc/html/static/FiraSans-Medium.woff2
Binary files differdiff --git a/src/librustdoc/html/static/FiraSans-Regular.woff2 b/src/librustdoc/html/static/FiraSans-Regular.woff2
new file mode 100644
index 00000000000..e766e06ccb0
--- /dev/null
+++ b/src/librustdoc/html/static/FiraSans-Regular.woff2
Binary files differdiff --git a/src/librustdoc/html/static/rustdoc.css b/src/librustdoc/html/static/rustdoc.css
index 56f17b7a616..e3d63fa2308 100644
--- a/src/librustdoc/html/static/rustdoc.css
+++ b/src/librustdoc/html/static/rustdoc.css
@@ -3,13 +3,17 @@
 	font-family: 'Fira Sans';
 	font-style: normal;
 	font-weight: 400;
-	src: local('Fira Sans'), url("FiraSans-Regular.woff") format('woff');
+	src: local('Fira Sans'),
+		url("FiraSans-Regular.woff2") format("woff2"),
+		url("FiraSans-Regular.woff") format('woff');
 }
 @font-face {
 	font-family: 'Fira Sans';
 	font-style: normal;
 	font-weight: 500;
-	src: local('Fira Sans Medium'), url("FiraSans-Medium.woff") format('woff');
+	src: local('Fira Sans Medium'),
+		url("FiraSans-Medium.woff2") format("woff2"),
+		url("FiraSans-Medium.woff") format('woff');
 }
 
 /* See SourceSerifPro-LICENSE.txt for the Source Serif Pro license. */