hgweb: improve colors for comparison page

delete: red -> red
insert: green -> yellow
change: yellow -> gray

mercurial/templates/static/style-coal.css

@@ -304,16 +304,16 b' ul#graphnodes li .info {'
 }
 
 .delete {
-    background-color: black;
-    color: white;
+    background-color: #faa;
+    color: #333;
 }
 
 .insert {
-    background-color: #d0d0d0;
+    background-color: #ffa;
 }
 
 .replace {
-    background-color: #f9f9f9;
+    background-color: #e8e8e8;
 }
 
 .header {

mercurial/templates/static/style-gitweb.css

@@ -144,15 +144,16 b' ul#graphnodes li .info {'
 }
 
 .delete {
-    background-color: #ffc5ce;
+    background-color: #faa;
+    color: #333;
 }
 
 .insert {
-    background-color: #c5ffc4;
+    background-color: #ffa;
 }
 
 .replace {
-    background-color: #ffff99;
+    background-color: #e8e8e8;
 }
 
 .comparison {

mercurial/templates/static/style-monoblue.css

@@ -496,15 +496,16 b' ul#graphnodes li .info {'
 }
 
 .delete {
-    background-color: #ffc5ce;
+    background-color: #faa;
+    color: #333;
 }
 
 .insert {
-    background-color: #c5ffc4;
+    background-color: #ffa;
 }
 
 .replace {
-    background-color: #ffff99;
+    background-color: #e8e8e8;
 }
 
 .comparison {

mercurial/templates/static/style-paper.css

@@ -293,15 +293,16 b' ul#graphnodes li .info {'
 }
 
 .delete {
-    background-color: #ffc5ce;
+    background-color: #faa;
+    color: #333;
 }
 
 .insert {
-    background-color: #c5ffc4;
+    background-color: #ffa;
 }
 
 .replace {
-    background-color: #ffff99;
+    background-color: #e8e8e8;
 }
 
 .header {

tests/test-hgweb.t

@@ -455,15 +455,16 b' static file'
   }
   
   .delete {
-      background-color: #ffc5ce;
+      background-color: #faa;
+      color: #333;
   }
   
   .insert {
-      background-color: #c5ffc4;
+      background-color: #ffa;
   }
   
   .replace {
-      background-color: #ffff99;
+      background-color: #e8e8e8;
   }
   
   .comparison {