CollectionBuilderAttribute.MethodName remarks contradict CollectionBuilderAttribute(Type, String) Constructor remarks

### Type of issue

Other (describe below)

### Description

The constructor remarks say the following:
> methodName must refer to a static method that accepts a single parameter of type [ReadOnlySpan\](https://learn.microsoft.com/en-us/dotnet/api/system.readonlyspan-1?view=net-9.0) and returns an instance of the collection being built containing a copy of the data from that span.

The MethodName property remarks state:
> This should match the metadata name of the target method. For example, this might be ".ctor" if targeting the type's constructor.

A constructor isn't a static method and can't return an instance of the collection. The constructor documentation says other patterns might be supported in the future, but currently using CollectionBuilderAttribute to specify creating it using the constructor isn't supported.

### Page URL

https://learn.microsoft.com/en-us/dotnet/api/system.runtime.compilerservices.collectionbuilderattribute.methodname?view=net-9.0&source=docs#system-runtime-compilerservices-collectionbuilderattribute-methodname

### Content source URL

https://github.com/dotnet/dotnet-api-docs-temp/blob/live/xml/System.Runtime.CompilerServices/CollectionBuilderAttribute.xml

### Document Version Independent Id

368975ed-1538-7808-0601-bff5a85acefd

### Platform Id

3bded7f0-22bf-9686-fc8b-1d65a64ef493

### Article author

@dotnet-bot

Open xml/System.Runtime.CompilerServices/CollectionBuilderAttribute.xml and compare the MethodName property remarks with the CollectionBuilderAttribute(Type, String) constructor remarks. Update the contradictory documentation so it accurately reflects the currently supported pattern, then verify the generated MethodName API page shows consistent wording.

Written by the indexing model from the issue text.