[vimrc] Fix blocks in switch case indentation

vim/after/ftplugin/c.vim

@@ -3,7 +3,7 @@
 " Indentation
 setlocal cindent
 setlocal si
-setlocal cinoptions=:0
+setlocal cinoptions+=:0
 setlocal shiftwidth=4
 setlocal noexpandtab
 

vimrc

@@ -312,6 +312,7 @@ set autoindent
 set copyindent
 set smartindent
 set cinwords=except,finally,def,class,with,do,if,elif,else,for,while,try,switch
+set cinoptions+=l1
 set modelines=1
 set shiftwidth=4
 set softtabstop=4