Update docs

doc/changelog.asciidoc

@@ -71,6 +71,8 @@ Added
 - New settings for the ABP-based adblocker:
    * `content.blocking.method` to decide which blocker(s) should be used.
    * `content.blocking.adblock.lists` to configure ABP-like lists to use.
+- New `qt.environ` setting which makes it easier to set/unset environment
+  variables for qutebrowser.
 - When QtWebEngine has been updated but PyQtWebEngine hasn't yet, the dark mode
   settings might stop working. As a (currently undocumented) escape hatch, this
   version adds a `QUTE_DARKMODE_VARIANT=qt_515_2` environment variable which can

doc/help/settings.asciidoc

@@ -271,6 +271,7 @@
 |<<prompt.filebrowser,prompt.filebrowser>>|Show a filebrowser in download prompts.
 |<<prompt.radius,prompt.radius>>|Rounding radius (in pixels) for the edges of prompts.
 |<<qt.args,qt.args>>|Additional arguments to pass to Qt, without leading `--`.
+|<<qt.environ,qt.environ>>|Additional environment variables to set.
 |<<qt.force_platform,qt.force_platform>>|Force a Qt platform to use.
 |<<qt.force_platformtheme,qt.force_platformtheme>>|Force a Qt platformtheme to use.
 |<<qt.force_software_rendering,qt.force_software_rendering>>|Force software rendering for QtWebEngine.
@@ -3471,6 +3472,17 @@ Type: <<types,List of String>>
 
 Default: empty
 
+[[qt.environ]]
+=== qt.environ
+Additional environment variables to set.
+Setting an environment variable to null/None will unset it.
+
+This setting requires a restart.
+
+Type: <<types,Dict>>
+
+Default: empty
+
 [[qt.force_platform]]
 === qt.force_platform
 Force a Qt platform to use.