Change the text width in Vim to 79.

Match other places (like flake8) and it shouldn't overflow.

.vimrc

@@ -2,7 +2,7 @@ filetype plugin indent on
 setlocal tabstop=4
 setlocal softtabstop=4
 setlocal shiftwidth=4
-setlocal textwidth=80
+setlocal textwidth=79
 setlocal smarttab
 setlocal expandtab
 setlocal incsearch