Glyph for the character U+2206 "INCREMENT"

[ollicle]

This unicode character is used by BBEdit and TextWrangler from BareBones to display tabs when “show invisibles” is enabled. FiraCode does not include this glyph so as a result the tabs are displayed a [?].

See issue #274 for screenshots. Note, this appears to be a separate problem to the duplicated punctuation described by #274. Older versions of FiraCode are missing the INCREMENT glyph, but do not duplicate punctuation after TAB.