Fixes #11899: Ensure proper margins and .small/small usage for heading tags (e.g., .h1-.h6)

dist/css/bootstrap.css

@@ -378,31 +378,49 @@ h6 .small,
   color: #999;
 }
 h1,
+.h1,
 h2,
-h3 {
+.h2,
+h3,
+.h3 {
   margin-top: 20px;
   margin-bottom: 10px;
 }
 h1 small,
+.h1 small,
 h2 small,
+.h2 small,
 h3 small,
+.h3 small,
 h1 .small,
+.h1 .small,
 h2 .small,
-h3 .small {
+.h2 .small,
+h3 .small,
+.h3 .small {
   font-size: 65%;
 }
 h4,
+.h4,
 h5,
-h6 {
+.h5,
+h6,
+.h6 {
   margin-top: 10px;
   margin-bottom: 10px;
 }
 h4 small,
+.h4 small,
 h5 small,
+.h5 small,
 h6 small,
+.h6 small,
 h4 .small,
+.h4 .small,
 h5 .small,
-h6 .small {
+.h5 .small,
+h6 .small,
+.h6 .small {
   font-size: 75%;
 }
 h1,

less/type.less

@@ -21,9 +21,9 @@ h1, h2, h3, h4, h5, h6,
   }
 }
 
-h1,
-h2,
-h3 {
+h1, .h1,
+h2, .h2,
+h3, .h3 {
   margin-top: @line-height-computed;
   margin-bottom: (@line-height-computed / 2);
 
@@ -32,9 +32,9 @@ h3 {
     font-size: 65%;
   }
 }
-h4,
-h5,
-h6 {
+h4, .h4,
+h5, .h5,
+h6, .h6 {
   margin-top: (@line-height-computed / 2);
   margin-bottom: (@line-height-computed / 2);