\H wiki argument

If given, show a link to the Wikipedia article that corresponds to the header.

If a value is not given, automatically link to the Wiki page that matches the header exactly with spaces converted to underscores.

Use an explicit value only when the Wikipedia page differs from the title. Redundant explicit values are an error; use {wiki} instead.

Here is an example with an explicit wiki argument:

==== Beijing's Tiananmen Square
{wiki=Tiananmen_Square}

which looks like: