Cache properties before emmiting a signal on document reset

This method:

• Checks property changes before emitting signals, reducing signal emissions when properties are unchanged.
• Slightly slower per call due to property getter overhead (e.g., creating a copy of QTextCursor for fontFamily(), bold(), etc.).
• Likely faster overall since QML slots are expensive, as it minimizes unnecessary UI updates.

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For a benchmark, let's try to minimize calls with Qt.callLater(func):

Use this function to eliminate redundant calls to a function or signal.

Qt.callLater(() => handler.benchmarkResetMethods(1000));

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Benchmarks

Run #1

Starting benchmark for 1000 iterations...
"resetOriginal" took 2018 ms for 1000 iterations
"resetOptimized" took 36 ms for 1000 iterations
Benchmark complete.

Run #2

Starting benchmark for 1000 iterations...
"resetOriginal" took 2021 ms for 1000 iterations
"resetOptimized" took 39 ms for 1000 iterations
Benchmark complete.

Run #3

Starting benchmark for 1000 iterations...
"resetOriginal" took 2042 ms for 1000 iterations
"resetOptimized" took 38 ms for 1000 iterations
Benchmark complete.

• resetOriginal is the original impl.

• resetOptimized is the commit impl.

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Notes

• 1000 iterations simulate frequent calls (e.g., ~3–5 minutes of typing at 60 WPM).
• Use QElapsedTimer as it provides high-resolution timing, ensuring accurate measurements.
• QTimer with a 0 ms interval runs as fast as the event loop allows, but there’s minimal overhead per iteration.
• This MR also fixes a wrong signal usage (see second commit).