on my computer it opens your favorites but if you are typing it puts a diaeresis over the a

The separation or resolution of one syllable into two; -- the opposite of synaeresis., A mark consisting of two dots [/], placed over the second of two adjacent vowels, to denote that they are to be pronounced as distinct letters; as, cooperate, aerial., Same as Diaeresis.

Umlaut in German, Diaeresis/trema in other languages.

It is spelled "Loïc" in French with the two dots over the "i" called a diaeresis.

The two dots above a letter, you mean, would be called a diaeresis and/or an umlaut.