QDoc: Resolve QML method links with signatures

Dotted QML method links cannot distinguish overloads by parameter
type. Authors must switch to C++ notation to select a particular
overload. Malformed signatures can also silently select an overload,
leaving readers with misleading links.

Allow dotted references to select QML method overloads and sections
in their documentation. Preserve C++-style references and warn about
invalid signatures instead of silently choosing a target.

[ChangeLog][QDoc] QML method links support dotted syntax with parameter
types for overload selection. Invalid signatures produce warnings
instead of silently selecting an overload.

Pick-to: 6.12
Task-number: QTBUG-137279
Change-Id: I2cdc1a2b7aa1f7d88b4f915cb2e822045c24ce40
Reviewed-by: Topi Reinio <topi.reinio@qt.io>