Serialize float headers correctly

Author: JordonPhillips

packages/smithy-http/src/smithy_http/serializers.py

@@ -481,15 +481,15 @@ def write_big_integer(self, schema: Schema, value: int) -> None:
 
     def write_float(self, schema: Schema, value: float) -> None:
         key = self._key or schema.expect_trait(HTTPHeaderTrait).key
-        self.headers.append((key, str(value)))
+        self.headers.append((key, serialize_float(value)))
 
     def write_double(self, schema: Schema, value: float) -> None:
         key = self._key or schema.expect_trait(HTTPHeaderTrait).key
-        self.headers.append((key, str(value)))
+        self.headers.append((key, serialize_float(value)))
 
     def write_big_decimal(self, schema: Schema, value: Decimal) -> None:
         key = self._key or schema.expect_trait(HTTPHeaderTrait).key
-        self.headers.append((key, str(value.canonical())))
+        self.headers.append((key, serialize_float(value)))
 
     def write_string(self, schema: Schema, value: str) -> None:
         key = self._key or schema.expect_trait(HTTPHeaderTrait).key