Modify plugin_ffi and package_ffi template

[HosseinYousefi]

• Use dart run instead of flutter pub run in the documentation as it is now deprecated.
• Use int64_t instead of intptr_t for sum examples.

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[dcharkes]

🙏 @HosseinYousefi

• Use int64_t instead of intptr_t for sum examples.

I have no objection against this. However, I believe it was consistent before with IntPtr in Dart and intptr_t in C as well. Any particular reason why we should prefer int64_t instead? (If we want to go vanilla C, we could consider going for int and Int instead.)

[HosseinYousefi]

🙏 @HosseinYousefi

• Use int64_t instead of intptr_t for sum examples.

I have no objection against this. However, I believe it was consistent before with IntPtr in Dart and intptr_t in C as well. Any particular reason why we should prefer int64_t instead? (If we want to go vanilla C, we could consider going for int and Int instead.)

Just felt weird to sum two pointers. Usually we sum two normal numbers (or size_ts maybe).

[dcharkes]

Just felt weird to sum two pointers. Usually we sum two normal numbers (or size_ts maybe).

They are not pointers. They are just word-size integers (which happens to be the same amount of bytes as a pointer). Pointers would be bla* and Pointer<Bla>?

Maybe let's just go for int and Int, those distract the least from the actual setup that the templates serve as an example for.

[HosseinYousefi]

Just felt weird to sum two pointers. Usually we sum two normal numbers (or size_ts maybe).

They are not pointers. They are just word-size integers (which happens to be the same amount of bytes as a pointer). Pointers would be bla* and Pointer<Bla>?

Maybe let's just go for int and Int, those distract the least from the actual setup that the templates serve as an example for.

I understand that they're not pointers. I wanted to go with something less distracting though. Int sounds good. I will change that.