I would like to type bra-keted expression
into the document. How do I do that?
The Docs support a little bit of TeX syntax, but apparently not \langle and \rangle. It seems the best we can do is to use Unicode characters:
U+27E8 ⟨ Mathematical left angle bracket U+27E9 ⟩ Mathematical right angle bracket
There may be a way to type these, but I haven't succeeded, and just copy-pasted them from Wikipedia page for this Unicode block
They look good in a formula, except that, being ordinary characters, they don't scale with the size of the expression they contain.
Another way is to search for "bracket" in the special characters option of the insert menu of Google Docs. There it has the angular brackets which you can use either in the text or equations.