Don't display stderr for the testing command in check.sh's runif;

And remove an obsolete comment in check-clippy.sh.

check-clippy.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 set -euo pipefail
 
-# Usage: check-clippy.sh [--install]
+# Usage: check-clippy.sh
 
 if cargo install --list | tee /dev/null | grep -q "^clippy v0"; then
     exit 0

lib/codegen/meta/check.sh

@@ -4,7 +4,7 @@ topdir=$(dirname "$0")
 cd "$topdir"
 
 function runif {
-    if type "$1" > /dev/null; then
+    if type "$1" > /dev/null 2>&1; then
         version=$("$1" --version 2>&1)
         echo "   === $1: $version ==="
         "$@"