Unbind Ctrl-Shift-Tab by default

doc/help/settings.asciidoc

@@ -500,6 +500,7 @@ Default:
 * +pass:[<Ctrl-Return>]+: +pass:[follow-selected -t]+
 * +pass:[<Ctrl-Shift-N>]+: +pass:[open -p]+
 * +pass:[<Ctrl-Shift-T>]+: +pass:[undo]+
+* +pass:[<Ctrl-Shift-Tab>]+: +pass:[nop]+
 * +pass:[<Ctrl-Shift-W>]+: +pass:[close]+
 * +pass:[<Ctrl-T>]+: +pass:[open -t]+
 * +pass:[<Ctrl-Tab>]+: +pass:[tab-focus last]+

qutebrowser/config/configdata.yml

@@ -2330,6 +2330,7 @@ bindings.default:
       gf: view-source
       gt: set-cmd-text -s :buffer
       <Ctrl-Tab>: tab-focus last
+      <Ctrl-Shift-Tab>: nop
       <Ctrl-^>: tab-focus last
       <Ctrl-V>: enter-mode passthrough
       <Ctrl-Q>: quit