Both PhpDoc (phpDocumentor) and doxygen support inline-link to other method.
For phpDocumentor
Use:
{@link myOtherMethod()}
Or:
{@link MyClass::myOtherMethod()}
But unlike doxygen, seems inline-link is not everywhere supported,
see PhpDocs: Link to another method in "@deprecated" tag's description?
For doxygen:
{@link #myOtherMethod}
Or:
{@link MyClass#myOtherMethod}
Or even just:
myOtherMethod()
Note that human-readability of un-compiled docs matters,
hence phpDocumentor syntax should be used, because it's more known (by PHP developers at least).
But once doxygen supports that same PhpDoc syntax, it's no issue to generate docs with doxygen, because once docs are compiled, it does not matter with what tool they were compiled, they are readable either way.