Small edit on who funds the channel. (#767)

Small edit on who funds the channel as well as expanded the footnote to mention experimental dual-funded channels currently in c-lightning.

03_how_ln_works.asciidoc

@@ -124,7 +124,7 @@ Multisignature scripts and addresses are explained in more detail in <<multisig>
 
 ==== Funding transaction
 
-The fundamental building block of a payment channel, is a 2-of-2 multisignature address. The two channel partners fund the payment channel by sending bitcoin to the multisignature address. This transaction is called the _funding transaction_, and is recorded on the Bitcoin blockchain. footnote:[While the original Lightning whitepaper described channels funded by both channel partners, the current specification, as of 2020, assumes that just one partner commits funds to the channel.]
+The fundamental building block of a payment channel, is a 2-of-2 multisignature address. One of the two channel partners will fund the payment channel by sending bitcoin to the multisignature address. This transaction is called the _funding transaction_, and is recorded on the Bitcoin blockchain. footnote:[While the original Lightning whitepaper described channels funded by both channel partners, the current specification, as of 2020, assumes that just one partner commits funds to the channel. As of May 2021 dual-funded lightning channels are experimental in the c-lightning LN implementation.]
 
 Even though the funding transaction is public, it is not obvious that it is a Lightning payment channel until it is closed. Furthermore, channel payments are still not visible to anyone other than the channel partners, nor is the distribution of the channel balance between them.