manual: document builtins.functionArgs

The text is just a conversion of comment from src/libexpr/primops.cc

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libexpr/primops.cc b/src/libexpr/primops.cc
index 5b9ecc018f..cf2d3d278f 100644
--- a/src/libexpr/primops.cc
+++ b/src/libexpr/primops.cc
@@ -1154,7 +1154,7 @@ static void prim_catAttrs(EvalState & state, const Pos & pos, Value * * args, Va
 
 /* Return a set containing the names of the formal arguments expected
    by the function `f'.  The value of each attribute is a Boolean
-   denoting whether has a default value.  For instance,
+   denoting whether the corresponding argument has a default value.  For instance,
 
       functionArgs ({ x, y ? 123}: ...)
    => { x = false; y = true; }