Update doc/manual/src/command-ref/nix-instantiate.md

Co-authored-by: Robert Hensing <[email protected]>

doc/manual/src/command-ref/nix-instantiate.md

@@ -47,7 +47,7 @@ standard input.
     > This option produces output which can be parsed as a Nix expression which
     > will produce a different result than the input expression when evaluated.
     > For example, these two Nix expressions print the same result despite
-    > having different values:
+    > having different meaning:
     >
     > ```console
     > $ nix-instantiate --eval --expr '{ a = {}; }'