doc: generate documentation for askrene-bias-node.

I noticed it was missing.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Author: rustyrussell

doc/Makefile

@@ -8,6 +8,7 @@ MARKDOWNPAGES := doc/addgossip.7 \
 	doc/addpsbtoutput.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/index.rst

@@ -16,6 +16,7 @@ Core Lightning Documentation
    addpsbtoutput <addpsbtoutput.7.md>
    askrene-age <askrene-age.7.md>
    askrene-bias-channel <askrene-bias-channel.7.md>
+   askrene-bias-node <askrene-bias-node.7.md>
    askrene-create-channel <askrene-create-channel.7.md>
    askrene-create-layer <askrene-create-layer.7.md>
    askrene-disable-node <askrene-disable-node.7.md>