Create document that describes how to fix `Did not find functions with language [<runtime>]`

We do not have any public documentation that describes how to fix this error. We need guidance for both `dotnet` and `dotnet-isolated` runtimes. After we have this new doc, we can create an aka link and update the error message to redirect the user to this new doc when the exception it thrown for dotnet and dotnet-isolated apps only.

For reference, here is a thread on how to fix this issue:
https://stackoverflow.com/questions/69104798/error-did-not-find-functions-with-language-dotnet-isolated-in-azure-function

Also, below is an answer on how to fix this issue from ChatGPT:
The error message "Did not find functions with language [dotnet]" indicates that the Azure Function App is not detecting any functions written in the .NET language. This error can occur if the necessary configurations or files are missing. Here are a few steps to help you troubleshoot and resolve the issue:
1. Verify Function App Structure: Ensure that your Function App project has the correct structure for .NET functions. The main function code should be placed in a folder named "Functions" or "Function" (depending on the version of Azure Functions).
2. Function Metadata: Each function should have appropriate metadata defined in the function code file. Check that each function contains the necessary attributes, such as `[FunctionName]` and `[EntryPoint]` (for .NET 3.x or higher).
3. Runtime Version: Confirm that the Function App is set to use the correct version of the Azure Functions runtime that supports the .NET language. The appropriate runtime version depends on the version of Azure Functions and the .NET runtime you are using.
4. Language Worker Process: Ensure that the correct language worker process is present and running. The language worker process handles the execution of functions written in a specific language. Make sure the .NET language worker process is installed and running in the Azure Function App environment.
5. Configuration Files: Check the presence and content of the necessary configuration files, such as `host.json` and `function.json`. These files define the behavior and bindings for your functions. Ensure that they are correctly configured and located in the appropriate directories.
6. Deploy Dependencies: If you are deploying the Function App, ensure that you have included all the required dependencies and libraries for your .NET functions. Missing dependencies can prevent the functions from being detected.
7. Log Analysis: Check the Function App logs for any error or warning messages that could provide more insight into the issue. Reviewing the logs can help identify specific problems or misconfigurations.
By going through these steps, you should be able to identify and resolve the issue causing the "Did not find functions with language [dotnet]" error in your Function App.

Could you please add any information that might be missing and remove anything that is incorrect? Thank you.

Start by reviewing the linked Stack Overflow thread and the reported “Did not find functions with language” error context. Produce public guidance covering both dotnet and dotnet-isolated runtimes, correcting the listed troubleshooting steps and removing inaccurate information. Done means the document explains how users can resolve the error and is ready for a future aka link and error-message update.

Written by the indexing model from the issue text.