Bind Shift-Escape in insert mode

doc/changelog.asciidoc

@@ -53,6 +53,8 @@ Changed
     URL.
   * `--always-show-selection` to confirm the password to be entered even if
     there's only a single match.
+- In insert mode, `<Shift-Escape>` is now bound to `fake-key <Escape>` by
+  default, i.e., sends an Escape keypress to the website.
 
 [[v2.3.1]]
 v2.3.1 (2021-07-28)

doc/help/settings.asciidoc

@@ -546,6 +546,7 @@ Default:
 
 * +pass:[<Ctrl-E>]+: +pass:[edit-text]+
 * +pass:[<Escape>]+: +pass:[mode-leave]+
+* +pass:[<Shift-Escape>]+: +pass:[fake-key <Escape>]+
 * +pass:[<Shift-Ins>]+: +pass:[insert-text -- {primary}]+
 - +pass:[normal]+:
 

qutebrowser/config/configdata.yml

@@ -3653,6 +3653,7 @@ bindings.default:
       <Ctrl-E>: edit-text
       <Shift-Ins>: insert-text -- {primary}
       <Escape>: mode-leave
+      <Shift-Escape>: fake-key <Escape>
     hint:
       <Return>: hint-follow
       <Ctrl-R>: hint --rapid links tab-bg