aspnetcore: Scaffolding command in official documentation is broken (on Linux, at least)

Describe the bug

The following scaffold command from this page in the official documentation is broken:

dotnet aspnet-codegenerator identity -dc WebApp1.Data.ApplicationDbContext --files "Account.Register;Account.Login;Account.Logout;Account.RegisterConfirmation"

To Reproduce

Here are the exact commands that reliably reproduce the bug on my system, including my attempts to fix it (installing requested packages) and the exact error messages:

[david@blue c#-projects]$ cd /tmp                    
[david@blue /tmp]$ dotnet new webapp --auth Individual -o WebApp1
The template "ASP.NET Core Web App" was created successfully.
This template contains technologies from parties other than Microsoft, see https://aka.ms/aspnetcore/3.1-third-party-notices for details.

Processing post-creation actions...
Running 'dotnet restore' on WebApp1/WebApp1.csproj...
  Restore completed in 102.71 ms for /tmp/WebApp1/WebApp1.csproj.

Restore succeeded.

[david@blue /tmp]$ cd WebApp1 
[david@blue WebApp1]$ dotnet aspnet-codegenerator identity -dc WebApp1.Data.ApplicationDbContext --files "Account.Register;Account.Login;Account.Logout;Account.RegisterConfirmation"
Building project ...
Scaffolding failed.
Add Microsoft.VisualStudio.Web.CodeGeneration.Design package to the project as a NuGet package reference.
To see more information, enable tracing by setting environment variable 'codegen_trace' = 1.
RunTime 00:00:04.36
[david@blue WebApp1]$ dotnet add package Microsoft.VisualStudio.Web.CodeGeneration.Design                                                                                            
  Writing /tmp/tmpuDeUwH.tmp
info : Adding PackageReference for package 'Microsoft.VisualStudio.Web.CodeGeneration.Design' into project '/tmp/WebApp1/WebApp1.csproj'.
info : Restoring packages for /tmp/WebApp1/WebApp1.csproj...
info :   GET https://api.nuget.org/v3-flatcontainer/microsoft.visualstudio.web.codegeneration.design/index.json
info :   OK https://api.nuget.org/v3-flatcontainer/microsoft.visualstudio.web.codegeneration.design/index.json 19ms
info : Package 'Microsoft.VisualStudio.Web.CodeGeneration.Design' is compatible with all the specified frameworks in project '/tmp/WebApp1/WebApp1.csproj'.
info : PackageReference for package 'Microsoft.VisualStudio.Web.CodeGeneration.Design' version '3.1.4' added to file '/tmp/WebApp1/WebApp1.csproj'.
info : Committing restore...
info : Generating MSBuild file /tmp/WebApp1/obj/WebApp1.csproj.nuget.g.props.
info : Writing assets file to disk. Path: /tmp/WebApp1/obj/project.assets.json
log  : Restore completed in 515.17 ms for /tmp/WebApp1/WebApp1.csproj.
[david@blue WebApp1]$ dotnet aspnet-codegenerator identity -dc WebApp1.Data.ApplicationDbContext --files "Account.Register;Account.Login;Account.Logout;Account.RegisterConfirmation"
Building project ...
Finding the generator 'identity'...
Running the generator 'identity'...
Please install the following packages to your project for scaffolding identity: Microsoft.EntityFrameworkCore.SqlServer
   at Microsoft.VisualStudio.Web.CodeGeneration.ActionInvoker.<BuildCommandLine>b__6_0()
   at Microsoft.Extensions.CommandLineUtils.CommandLineApplication.Execute(String[] args)
   at Microsoft.VisualStudio.Web.CodeGeneration.ActionInvoker.Execute(String[] args)
   at Microsoft.VisualStudio.Web.CodeGeneration.CodeGenCommand.Execute(String[] args)
RunTime 00:00:04.68
[david@blue WebApp1]$ dotnet add package Microsoft.EntityFrameworkCore.SqlServer                                                                                                     
  Writing /tmp/tmpbouOSr.tmp
info : Adding PackageReference for package 'Microsoft.EntityFrameworkCore.SqlServer' into project '/tmp/WebApp1/WebApp1.csproj'.
info : Restoring packages for /tmp/WebApp1/WebApp1.csproj...
info :   GET https://api.nuget.org/v3-flatcontainer/microsoft.entityframeworkcore.sqlserver/index.json
info :   OK https://api.nuget.org/v3-flatcontainer/microsoft.entityframeworkcore.sqlserver/index.json 153ms
info : Package 'Microsoft.EntityFrameworkCore.SqlServer' is compatible with all the specified frameworks in project '/tmp/WebApp1/WebApp1.csproj'.
info : PackageReference for package 'Microsoft.EntityFrameworkCore.SqlServer' version '3.1.8' added to file '/tmp/WebApp1/WebApp1.csproj'.
info : Committing restore...
info : Writing assets file to disk. Path: /tmp/WebApp1/obj/project.assets.json
log  : Restore completed in 420.98 ms for /tmp/WebApp1/WebApp1.csproj.
[david@blue WebApp1]$ dotnet aspnet-codegenerator identity -dc WebApp1.Data.ApplicationDbContext --files "Account.Register;Account.Login;Account.Logout;Account.RegisterConfirmation"
Building project ...
Finding the generator 'identity'...
Running the generator 'identity'...
A file matching the name Account.Register.cs.cshtml was not found within any of the folders: 
   at Microsoft.VisualStudio.Web.CodeGeneration.ActionInvoker.<BuildCommandLine>b__6_0()
   at Microsoft.Extensions.CommandLineUtils.CommandLineApplication.Execute(String[] args)
   at Microsoft.VisualStudio.Web.CodeGeneration.ActionInvoker.Execute(String[] args)
   at Microsoft.VisualStudio.Web.CodeGeneration.CodeGenCommand.Execute(String[] args)
RunTime 00:00:05.93
[david@blue WebApp1]$ 

Exceptions (if any)

See previous section

Further technical details

ASP.NET Core version is in dotnet info. The issue takes place when using solely the dotnet command with no IDE.

$ dotnet --info                                                                                                                                                  
.NET Core SDK (reflecting any global.json):
 Version:   3.1.108
 Commit:    c423b556b5

Runtime Environment:
 OS Name:     arch
 OS Version:  
 OS Platform: Linux
 RID:         arch-x64
 Base Path:   /usr/share/dotnet/sdk/3.1.108/

Host (useful for support):
  Version: 3.1.8
  Commit:  05a0c8f6b1

.NET Core SDKs installed:
  3.1.108 [/usr/share/dotnet/sdk]

.NET Core runtimes installed:
  Microsoft.AspNetCore.App 3.1.8 [/usr/share/dotnet/shared/Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 3.1.8 [/usr/share/dotnet/shared/Microsoft.NETCore.App]

To install additional .NET Core runtimes or SDKs:
  https://aka.ms/dotnet-download