Update src/libexpr/primops.cc

src/libexpr/primops.cc

@@ -3183,7 +3183,7 @@ static RegisterPrimOp primop_foldlStrict({
       ...`. For example, `foldl' (x: y: x + y) 0 [1 2 3]` evaluates to 6.
       The return value of each application of `op` is evaluated immediately,
       even for intermediate values. The first argument of the operation
-      (`x` in the example above) is the accumulator wheres the second one
+      (`x` in the example above) is the accumulator whereas the second one
       (`y`) is the next element.
     )",
     .fun = prim_foldlStrict,