Add httpPrefixHeaders trait support

Author: JordonPhillips

smithy-docgen-core/src/main/java/software/amazon/smithy/docgen/core/integrations/BuiltinsIntegration.java

@@ -17,6 +17,7 @@
 import software.amazon.smithy.docgen.core.interceptors.ExternalDocsInterceptor;
 import software.amazon.smithy.docgen.core.interceptors.HttpInterceptor;
 import software.amazon.smithy.docgen.core.interceptors.HttpLabelInterceptor;
+import software.amazon.smithy.docgen.core.interceptors.HttpPrefixHeadersInterceptor;
 import software.amazon.smithy.docgen.core.interceptors.HttpQueryInterceptor;
 import software.amazon.smithy.docgen.core.interceptors.HttpQueryParamsInterceptor;
 import software.amazon.smithy.docgen.core.interceptors.IdempotencyInterceptor;
@@ -91,6 +92,7 @@ public List<? extends CodeInterceptor<? extends CodeSection, DocWriter>> interce
                 new XmlAttributeInterceptor(),
                 new XmlNameInterceptor(),
                 new XmlFlattenedInterceptor(),
+                new HttpPrefixHeadersInterceptor(),
                 new HttpQueryParamsInterceptor(),
                 new HttpQueryInterceptor(),
                 new HttpLabelInterceptor(),

smithy-docgen-core/src/main/java/software/amazon/smithy/docgen/core/interceptors/HttpPrefixHeadersInterceptor.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package software.amazon.smithy.docgen.core.interceptors;
+
+import software.amazon.smithy.docgen.core.sections.ProtocolSection;
+import software.amazon.smithy.docgen.core.writers.DocWriter;
+import software.amazon.smithy.model.shapes.ShapeId;
+import software.amazon.smithy.model.traits.HttpPrefixHeadersTrait;
+import software.amazon.smithy.utils.SmithyInternalApi;
+
+/**
+ * Adds information about header bindings from the
+ * <a href="https://smithy.io/2.0/spec/http-bindings.html#httpprefixheaders-trait">
+ * httpPrefixHeaders trait</a> if the protocol supports it.
+ */
+@SmithyInternalApi
+public final class HttpPrefixHeadersInterceptor extends ProtocolTraitInterceptor<HttpPrefixHeadersTrait> {
+    @Override
+    protected Class<HttpPrefixHeadersTrait> getTraitClass() {
+        return HttpPrefixHeadersTrait.class;
+    }
+
+    @Override
+    protected ShapeId getTraitId() {
+        return HttpPrefixHeadersTrait.ID;
+    }
+
+    @Override
+    void write(DocWriter writer, String previousText, ProtocolSection section, HttpPrefixHeadersTrait trait) {
+        writer.putContext("prefix", trait.getValue());
+        writer.write("""
+                Each pair in this map represents an HTTP header${?prefix} with the prefix \
+                ${prefix:`}${/prefix}.
+
+                $L""", previousText);
+    }
+}