Some small dartdoc issues in the SDK

[parlough]

Dart SDK Version: 7551b9c

I created a CL with my best take on the fixes here - https://dart-review.googlesource.com/c/sdk/+/103741

• Stream#drain doc missing new paragraph line and references a function it doesn't call.
• Unresolved doc references in base64.dart due to not being able to link to methods from variables.
• Similar unresolved references in json.dart due to not being able to link to methods from variables.
• The doc references [value] instead of [object] inside jsonEncode
• Map identity factory doc links to == operator wrong.
• RegExp#isDotAll doc uses wrong capitalization on [isMultiLine] breaking link.
• Various improper linking in RawSocketOption
• In Stdin terminal is spelt wrong, breaking the linking
• js_dart2js.dart attempts to link to an apply method without the class type where it resides.
• Random's class dartdoc improperly links to the Random.secure constructor

[srawlins]

Thanks much!

[parlough]

Fixed by bb87996