This is not a duplicate of Keyboard shortcut Ctrl+K in comments conflicts with latest Firefox version because that only mentions comments, not posts.
While editing a long answer with a large block of text to quote, I held my mouse over the button for quoting, and noted that the shortcut to add quotes is Ctrl+Q.
The use of 'Q' makes sense, but it is also used to quit at least Firefox and Vivaldi.
Please note that this is not a question about adding comments and formatting of comments - this is in the main edit box, where questions are asked or answered.
Can this be changed in the website?