Use inherit on alert-heading color

Heading then inherits from the parent alert.
Avoids a lot of extra unneccessary CSS.

docs/assets/css/bootstrap.css

@@ -2132,10 +2132,11 @@ button.btn.small, input[type="submit"].btn.small {
   -webkit-border-radius: 4px;
   -moz-border-radius: 4px;
   border-radius: 4px;
-}
-.alert, .alert-heading {
   color: #c09853;
 }
+.alert-heading {
+  color: inherit;
+}
 .alert .close {
   position: relative;
   top: -2px;
@@ -2145,25 +2146,16 @@ button.btn.small, input[type="submit"].btn.small {
 .alert-success {
   background-color: #dff0d8;
   border-color: #d6e9c6;
-}
-.alert-success, .alert-success .alert-heading {
   color: #468847;
 }
 .alert-danger, .alert-error {
   background-color: #f2dede;
   border-color: #eed3d7;
-}
-.alert-danger,
-.alert-error,
-.alert-danger .alert-heading,
-.alert-error .alert-heading {
   color: #b94a48;
 }
 .alert-info {
   background-color: #d9edf7;
   border-color: #bce8f1;
-}
-.alert-info, .alert-info .alert-heading {
   color: #3a87ad;
 }
 .alert-block {

less/alerts.less

@@ -9,10 +9,10 @@
   background-color: @warningBackground;
   border: 1px solid @warningBorder;
   .border-radius(4px);
+  color: @warningText;
 }
-.alert,
 .alert-heading {
-  color: @warningText;
+  color: inherit;
 }
 
 // Adjust close link position
@@ -29,32 +29,20 @@
 .alert-success {
   background-color: @successBackground;
   border-color: @successBorder;  
-}
-.alert-success,
-.alert-success .alert-heading {
   color: @successText;
 }
 .alert-danger,
 .alert-error {
   background-color: @errorBackground;
   border-color: @errorBorder;
-}
-.alert-danger,
-.alert-error,
-.alert-danger .alert-heading,
-.alert-error .alert-heading {
   color: @errorText;
 }
 .alert-info {
   background-color: @infoBackground;
   border-color: @infoBorder;
-}
-.alert-info,
-.alert-info .alert-heading {
   color: @infoText;
 }
 
-
 // Block alerts
 // ------------------------
 .alert-block {