[README] update annotations with correct types

[odow]

Closes #408

My guess is that our friend Clong is Int64 on nix and Int32 on Windows. CPLEX really wants Clonglong here, which is the CPXLONG constant.

[codecov[bot]]

Codecov Report

Base: 43.46% // Head: 43.46% // No change to project coverage :thumbsup:

Coverage data is based on head (724de2b) compared to base (6e7be8e). Patch has no changes to coverable lines.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #409 +/- ## ======================================= Coverage 43.46% 43.46% ======================================= Files 8 8 Lines 5025 5025 ======================================= Hits 2184 2184 Misses 2841 2841 ``` Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=jump-dev). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=jump-dev)

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