docgen / dartdoc-viewer: link static methods when referenced as default values

[DartBot]

This issue was originally filed by @seaneagan

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For the following method:

min(Iterable iterable, {Comparator comparator = Comparable.compare});

Currently the docs just display the following unstyled text for the default value:

function(Comparable#compare)

It would be useful if it linked to the Comparable.compare docs instead, as references in docs do, with similar styling.

[DartBot]

This comment was originally written by @seaneagan

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"as references in doc comments do"

[iposva-google]

Added Area-DartDocViewer, Triaged labels.

[kevmoo]

This is work on the docgen side

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Removed Area-DartDocViewer label.
Added Area-Pkg, Pkg-DocGen labels.

[DartBot]

This comment was originally written by @seaneagan

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Actually, should have been more general. I would want to link to any public names referenced by the default value expression. Examples:

final Duration ANIM_DURATION_DEFAULT = const Duration(milliseconds: 500);
slideIn(Element el, {Duration duration : ANIM_DURATION_DEFAULT});
fadeIn(Element el, {Duration duration : ANIM_DURATION_DEFAULT});
// ...

addChild(Node child, [Node parent = const Node.root()]) // ...

rotate(num radians, {num min: -PI, max: PI}) // ...

[sethladd]

Moved to dart-lang/dartdoc#97

[sethladd]

Added MovedToGithub label.