#800 Re-enable API check (#878)

Author: Tratcher

src/Microsoft.AspNetCore.Http.Features/Microsoft.AspNetCore.Http.Features.csproj

@@ -8,7 +8,6 @@
     <NoWarn>$(NoWarn);CS1591</NoWarn>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageTags>aspnetcore</PackageTags>
-    <EnableApiCheck>false</EnableApiCheck>
   </PropertyGroup>
 
   <ItemGroup>

src/Microsoft.AspNetCore.Http.Features/breakingchanges.netcore.json

@@ -0,0 +1,12 @@
+[
+  {
+    "TypeId": "public interface Microsoft.AspNetCore.Http.IHeaderDictionary : System.Collections.Generic.IDictionary<System.String, Microsoft.Extensions.Primitives.StringValues>",
+    "MemberId": "System.Nullable<System.Int64> get_ContentLength()",
+    "Kind": "Addition"
+  },
+  {
+    "TypeId": "public interface Microsoft.AspNetCore.Http.IHeaderDictionary : System.Collections.Generic.IDictionary<System.String, Microsoft.Extensions.Primitives.StringValues>",
+    "MemberId": "System.Void set_ContentLength(System.Nullable<System.Int64> value)",
+    "Kind": "Addition"
+  }
+]

src/Microsoft.AspNetCore.Http.Features/exceptions.netcore.json

@@ -9,7 +9,6 @@
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <PackageTags>http</PackageTags>
-    <EnableApiCheck>false</EnableApiCheck>
   </PropertyGroup>
 
   <ItemGroup>