clean: simplify macOS hotkey mapping code

[shenlebantongying]

Let's merge this in another day,

Chop related code to half.

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This region of code looked scary because the first line assumes everyone uses English keyboard.

TISInputSourceRef inputSourceRef = TISCopyInputSourceForLanguage(CFSTR("en"));

So, the next line patches it by copying current input source -> TISCopyCurrentKeyboardInputSource

But japanese keyboard is slightly different, so it got patched again with TISCopyCurrentKeyboardLayoutInputSource

Just uses the last one TISCopyCurrentKeyboardLayoutInputSource, all code are no longer needed.

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Also change mappping to a vector instead of calloc.

[shenlebantongying]

Don't think this will bring any regression, because the simplified code user the thing that handles goldendict/goldendict#1419

Also tested other situations -> chinese input method & English

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud