Fix command documentation for publish (#818)

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## Motivation and Context
<!-- Why is this change needed? What problem does it solve? -->

The `--file=PATH` pattern does not work. The path is an optional,
positional argument not a named option.
The `--dry-run` option is not supported.

Look at the implementation:
https://github.com/modelcontextprotocol/registry/blob/d092dd6390f1c64add83303517c4d00bfc65433e/cmd/publisher/commands/publish.go#L19

## How Has This Been Tested?

Try these options yourself, they are ignored.

## Breaking Changes
<!-- Will users need to update their code or configurations? -->

## Types of changes
<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply: -->
- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to change)
- [x] Documentation update

## Checklist
<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->
- [x] I have read the [MCP
Documentation](https://modelcontextprotocol.io)
- [x] My code follows the repository's style guidelines
- [x] New and existing tests pass locally
- [x] I have added appropriate error handling
- [x] I have added or updated documentation as needed

## Additional context
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-->

Author: joelverhagen

docs/reference/cli/commands.md

@@ -215,30 +215,26 @@ For detailed guidance on the publishing process, see the [publishing guide](../.
 
 **Usage:**
 ```bash
-mcp-publisher publish [options]
+mcp-publisher publish [PATH]
 ```
 
 **Options:**
-- `--file=PATH` - Path to server.json (default: `./server.json`)
-- `--registry=URL` - Registry URL override
-- `--dry-run` - Validate without publishing
+- `PATH` - Path to server.json (default: `./server.json`)
 
 **Process:**
 1. Validates `server.json` against schema
-2. Verifies package ownership (see [Official Registry Requirements](../server-json/official-registry-requirements.md))
-3. Checks namespace authentication
-4. Publishes to registry
+2. Publishes the `server.json` to the registry server URL specified in the login token
+3. Server: Verifies package ownership (see [Official Registry Requirements](../server-json/official-registry-requirements.md))
+4. Server: Checks namespace authentication
+5. Server: Publishes to registry
 
 **Example:**
 ```bash
 # Basic publish
 mcp-publisher publish
 
-# Dry run validation
-mcp-publisher publish --dry-run
-
 # Custom file location  
-mcp-publisher publish --file=./config/server.json
+mcp-publisher publish ./config/server.json
 ```
 
 ### `mcp-publisher logout`