doc: Add signmessagewithkey to generate documentation

And sorted list with file name.

doc/Makefile

@@ -9,16 +9,16 @@ MARKDOWNPAGES := doc/addgossip.7 \
 	doc/askrene-age.7 \
 	doc/askrene-bias-channel.7 \
 	doc/askrene-bias-node.7 \
-	doc/askrene-create-layer.7 \
-	doc/askrene-remove-layer.7 \
 	doc/askrene-create-channel.7 \
-	doc/askrene-update-channel.7 \
+	doc/askrene-create-layer.7 \
 	doc/askrene-disable-node.7 \
 	doc/askrene-inform-channel.7 \
 	doc/askrene-listlayers.7 \
 	doc/askrene-listreservations.7 \
+	doc/askrene-remove-layer.7 \
 	doc/askrene-reserve.7 \
 	doc/askrene-unreserve.7 \
+	doc/askrene-update-channel.7 \
 	doc/autoclean-once.7 \
 	doc/autoclean-status.7 \
 	doc/batching.7 \
@@ -58,7 +58,7 @@ MARKDOWNPAGES := doc/addgossip.7 \
 	doc/disableoffer.7 \
 	doc/disconnect.7 \
 	doc/emergencyrecover.7 \
-	doc/enableoffer.7	\
+	doc/enableoffer.7 \
 	doc/exposesecret.7 \
 	doc/feerates.7 \
 	doc/fetchbip353.7 \
@@ -134,6 +134,7 @@ MARKDOWNPAGES := doc/addgossip.7 \
 	doc/showrunes.7 \
 	doc/signinvoice.7 \
 	doc/signmessage.7 \
+	doc/signmessagewithkey.7 \
 	doc/signpsbt.7 \
 	doc/splice_init.7 \
 	doc/splice_signed.7 \

doc/index.rst

@@ -150,6 +150,7 @@ Core Lightning Documentation
    showrunes <showrunes.7.md>
    signinvoice <signinvoice.7.md>
    signmessage <signmessage.7.md>
+   signmessagewithkey <signmessagewithkey.7.md>
    signpsbt <signpsbt.7.md>
    splice_init <splice_init.7.md>
    splice_signed <splice_signed.7.md>