Add examples Url methods

[ghost]

Fix issue #309

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This change is 

[bors-servo]

☔ The latest upstream changes (presumably #331) made this pull request unmergeable. Please resolve the merge conflicts.

[SimonSapin]

This includes a lot of unrelated changes in the same commit, making it difficult to find out what actually changed.

For example, using /*! … */ instead of //! for the crate’s doc-comment is deliberate: it make editing this very long comment much easier. Using two spaces before same-line comments is also a deliberate choice. Whitespace was added and removed at random places for no apparent reason.

[lucab]

@SimonSapin from a quick glance at this, the large diff seems to be due to a rustfmt pass. Perhaps you may want to do a repo-wide pass separately so that further PR can start from a clean base?

[dtolnay]

@hngnaig are you still working on rolling back those unrelated formatting changes?

[ghost]

@dtolnay sr for late, i still working on it, and commit rolling back those. :)

[ghost]

I open other PR to remove rustfmt