Please don't: when used for code, preserving lines (even when requiring scrolling on mobile) is a good thing. 100% width is fine, no reason it needs to be as narrow as it is.
If a blockquote format is desired, that's great, but don't change the code formatting to make it a slightly-less bad (but still horrible, because of monospacing) way of presenting blockquotes.
If a blockquote format is desired, that's great, but don't change the code formatting to make it a slightly-less bad (but still horrible, because of monospacing) way of presenting blockquotes.