docs: improve keyboard layout documentation

- Remove recommendation of XKB_* environment variables in river(1) as we
  now have a dedicated riverctl keyboard-layout command.

- Give an example of how to use and switch between multiple layouts in
  the riverctl(1) man page.

 doc/river.1.scd    | 17 -----------------
 doc/riverctl.1.scd | 15 +++++++++------
 2 files changed, 9 insertions(+), 23 deletions(-)

diff --git a/doc/river.1.scd b/doc/river.1.scd
index 9a76622..972cad1 100644
--- a/doc/river.1.scd
+++ b/doc/river.1.scd
@@ -50,23 +50,6 @@ Usually this executable is a shell script invoking *riverctl*(1) to create
 mappings, start programs such as a layout generator or status bar, and
 perform other configuration.
 
-# ENVIRONMENT
-
-The following environment variables are used to configure the keyboard. See
-*xkeyboard-config*(7) for possible values.
-
-- XKB_DEFAULT_MODEL
-- XKB_DEFAULT_LAYOUT
-- XKB_DEFAULT_VARIANT
-- XKB_DEFAULT_OPTIONS
-- XKB_DEFAULT_RULES
-
-# EXAMPLES
-
-Set the keyboard layout to colemak:
-
-	XKB_DEFAULT_LAYOUT="us(colemak)" river
-
 # AUTHORS
 
 Maintained by Isaac Freund <[email protected]> who is assisted by open
diff --git a/doc/riverctl.1.scd b/doc/riverctl.1.scd
index f8e46c9..3009a16 100644
--- a/doc/riverctl.1.scd
+++ b/doc/riverctl.1.scd
@@ -203,9 +203,9 @@ A complete list may be found in _/usr/include/linux/input-event-codes.h_
 	- _-layout_: if passed, a specific layout is pinned to the mapping.
 	  When the mapping is checked against a pressed key, this layout is
 	  used to translate the key independent of the active layout
-		- _index_: zero-based index of a layout set with the environment
-		  variable *XKB_DEFAULT_LAYOUT*; see *river*(1) for an example; if
-		  the index is out of range, the _-layout_ option will have no effect
+		- _index_: zero-based index of a layout set with the *keyboard-layout*
+		  command. If the index is out of range, the _-layout_ option will
+		  have no effect
 	- _mode_: name of the mode for which to create the mapping
 	- _modifiers_: one or more of the modifiers listed above, separated
 	  by a plus sign (+).
@@ -336,9 +336,12 @@ A complete list may be found in _/usr/include/linux/input-event-codes.h_
 
 *keyboard-layout* [-rules _rules_] [-model _model_] [-variant _variant_] \
 [-options _options_] _layout_
-	Set the XKB layout for all keyboards. Defaults from libxkbcommon are used
-	for everything left unspecified. See *xkeyboard-config*(7) for
-	possible values and more information.
+	Set the XKB layout for all keyboards. Defaults from libxkbcommon are used for
+	everything left unspecified. Note that *layout* may be a comma separated list
+	of layouts (e.g. "us,de") which may be switched between using various key
+	combinations configured through the options argument (e.g. -options
+	"grp:ctrl_space_toggle"). See *xkeyboard-config*(7) for possible values and
+	more information.
 
 *keyboard-group-create* _group_name_
 	Create a keyboard group. A keyboard group collects multiple keyboards in