release process: fix process for maintenance release

Author: jonasnick

doc/release-process.md

@@ -59,7 +59,7 @@ gcc -o ecdsa ecdsa.c -I $dir/include -L $dir/lib64/ -l secp256k1
 
 Note that bugfixes only need to be backported to releases for which no compatible release without the bug exists.
 
-1. If `$PATCH = 1`, create maintenance branch `$MAJOR.$MINOR`:
+1. If there's no maintenance branch `$MAJOR.$MINOR`, create one:
    ```
    git checkout -b $MAJOR.$MINOR v$MAJOR.$MINOR.0
    git push git@github.com:bitcoin-core/secp256k1.git $MAJOR.$MINOR