src: fix getopt format string

[bnoordhuis]

v8 inspect -l <n> takes an argument.

Bug introduced in commit 2fc1571 ("src: option to limit output of findjsinstances") from September 2018.

Fixes: https://github.com/nodejs/llnode/issues/346

[mmarchini]

We should add some testing here. Since we don't seem to have specific tests for command arguments, we can change one of the inspect tests:

diff --git test/plugin/inspect-test.js test/plugin/inspect-test.js
index 0a59c9b..f664237 100644
--- test/plugin/inspect-test.js
+++ test/plugin/inspect-test.js
@@ -244,7 +244,7 @@ const hashMapTests = {
       });
     }, (t, sess, addresses, name, cb) => {
       const address = addresses[name];
-      sess.send(`v8 inspect --array-length 1 ${address}`);
+      sess.send(`v8 inspect -l 1 ${address}`);

       sess.linesUntil(/\]>/, (err, lines) => {
         if (err) return cb(err);

We use --array-length on other places in this test, so it should be fine.

Also our documentation is incomplete, --array-length and --string-length are not documented, but this can be handled in a separate PR.

[bnoordhuis]

I updated one of the tests. I should perhaps mention that I don't plan to spend much more time on this patch, I just sent it because I'm such a nice guy (and also because obvious bug is obvious.)

[mmarchini]

Landed in 83c810faa06d