[gnome-system-monitor] src/interface: Fix call to CSS mix()

[Robert Roth <robertroth src gnome org>]

commit 5b401dd1470202ce315d8097e7f89d222a66298f
Author: Ondřej Míchal <harrymichal seznam cz>
Date:   Sun Apr 24 18:50:07 2022 +0300

    src/interface: Fix call to CSS mix()

 src/interface.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/interface.cpp b/src/interface.cpp
index 5b8ac6b5..926b7d2c 100644
--- a/src/interface.cpp
+++ b/src/interface.cpp
@@ -51,7 +51,7 @@ static const char* LOAD_GRAPH_CSS = "\
                       @theme_bg_color,\
                       @theme_base_color\
                       );\
-    color: mix (@theme_fg_color, @theme_bg_color, 0.5);\
+    color: mix(@theme_fg_color, @theme_bg_color, 0.5);\
 }\
 ";