Question: What diacritical mark was added to Te Atatu in 2008?

Context paragraphs:
Te Atatu Roosters: The Roosters play at the council owned Jack Colvin Park located in Te Atatu Peninsula, next to the North Western Motorway.  Junior teams play at Te Atatu Park, and at Gloria Park both also on the peninsula.

Te Atatu Peninsula: Te Atatu Peninsula, is an Auckland suburb formerly known as "Te Atatu North".  The 'peninsula' part was proposed by resident Emi Groot, in the early 1980s to replace 'north' and this was formally adopted in 1997.  Te Atatu is Maori for "the dawn".

Te Atatu South: Te Atatu South is a residential suburb in Auckland, New Zealand.  Te Atatu in Maori means "the dawn".

Diacritic: A diacritic – also diacritical mark, diacritical point, or diacritical sign – is a glyph added to a letter, or basic glyph.  The term derives from the Ancient Greek ("diakritikós", "distinguishing"), from διακρίνω ("diakrī́nō", "to distinguish").  "Diacritic" is primarily an adjective, though sometimes used as a noun, whereas "diacritical" is only ever an adjective.  Some diacritical marks, such as the acute ( ´ ) and grave ( ` ), are often called "accents".  Diacritical marks may appear above or below a letter, or in some other position such as within the letter or between two letters.

Macron (diacritic): A macron ( ) is a diacritical mark: it is a straight bar (¯) placed above a letter, usually a vowel.  Its name derives , since it was originally used to mark long or heavy syllables in Greco-Roman metrics.  It now more often marks a long vowel.  In the International Phonetic Alphabet, the macron is used to indicate a mid-tone; the sign for a long vowel is instead a modified triangular colon ⟨⟩ .

Te Atatu Peninsula Park: Te Atatu Peninsula Park is a park situated on the Te Atatu Peninsula.

Te Atatū (New Zealand electorate): Te Atatū (before 2008 styled Te Atatu, without macron) is a parliamentary electorate, returning one Member of Parliament to the New Zealand House of Representatives.  The current MP for Te Atatū is Phil Twyford of the Labour Party.

Waitakere Cricket Club: Waitakere Cricket Club is a cricket club based in Waitakere City.  Based at Te Atatu Park on the Te Atatu Peninsula, the club has won the Auckland club championship three times.

Te Atatu AFC: Te Atatu AFC is a semi-professional association football club in Te Atatu, New Zealand.  They are the currently competing in the US1 Premiership.

Te Atatu: Te Atatu (Maori for "the dawn") is the name of two suburbs in western Auckland, New Zealand: "Te Atatu Peninsula" and "Te Atatu South".  They are located next to each other some 10 kilometres to the west of the Auckland city centre.

Supporting paragraphs: Te Atatū (New Zealand electorate) Macron (diacritic)
Answer: macron