closes #1754

C# 14 support was added in #1658, but the website was not updated to
reflect this.

Co-authored-by: Bela VanderVoort <twobitbela@gmail.com>

Fixes the `java.io.IOException: Stream closed` exception that occurs
when the CSharpier process fails to start in the Rider plugin.

## Problem
The `onExit` handler was attempting to read from the error stream after
the process had exited, but streams are automatically closed when a
process terminates.

## Solution
Read stderr continuously in a background thread during the process
lifetime and capture output to a `StringBuilder`. The `onExit` handler
then references the captured output instead of trying to read from the
closed stream.

## Approach
This follows the pattern used in JetBrains' own code
(`ForkedByModuleSplitter`) for handling process streams safely, which
uses separate named threads to read stdout and stderr while the process
is running.

Co-authored-by: Bela VanderVoort <twobitbela@gmail.com>

closes #1760

closes #1759

closes #1771

)

There was an issue where if the left-hand side of `??` was even slightly
complex, the right-hand side would become part of the group and could
not have its own line.

I reconsidered the conditions for grouping and changed it from judging
the complexity of the left-hand side by a threshold to a condition where
"the left-hand side is an InvocationExpression and consists solely of
MemberAccessExpression that does not include an InvocationExpression".

fix #1769

## Summary

- Remove `Console.ReadKey()` in `ServerFormatter.cs` which throws
`InvalidOperationException` when CSharpier server is started by IDE
plugins (Rider, VS, VSCode) without a console attached
- The call was unreachable during normal operation since `RunAsync()`
blocks until shutdown

## Problem

When IDE plugins launch `csharpier server`, the process crashes
immediately with:

```
System.InvalidOperationException: Cannot read keys when either application does not have a console or when console input has been redirected.
   at System.ConsolePal.ReadKey(Boolean intercept)
   at CSharpier.Cli.Server.ServerFormatter.StartServer(...)
```

This manifests in Rider as "Process exited unexpectedly" errors.

Co-authored-by: Bela VanderVoort <twobitbela@gmail.com>