Add MarkerSize property documentation to chart markers topics

[Copilot]

Documents the newly introduced MarkerSize property across all language variants (en, jp, kr) of the chart markers feature topic.

Changes

• New section: Chart Marker Size — explains that MarkerSize sets exact device-independent pixel dimensions on any MarkerSeries-derived series, overriding template-driven sizing; resetting to NaN restores default behavior
• Interactive sample — added the scatter-marker-options sample to the Marker Size section, demonstrating MarkerSize on scatter series with an interactive editor
• Multi-platform code examples — covers Blazor (Razor), React (TSX), and Web Components (HTML):

<IgbScatterLineSeries MarkerSize="30" MarkerType="Circle" ... />

<IgrScatterLineSeries markerSize={30} markerType="Circle" ... />

<igc-scatter-line-series marker-size="30" marker-type="Circle" ...></igc-scatter-line-series>

• BubbleSeries caveat — notes that MarkerSize has no effect on bubble radius, which remains data/scale-driven
• Updated frontmatter — mentionedTypes extended with MarkerSeries, ScatterLineSeries, ScatterSplineSeries, ScatterSeries, LineSeries, SplineSeries; _keywords updated to include "Marker Size"
• API References — added MarkerSize, UseLightweightMarkers, and XamDataChart

[mtsvyatkova]

@copilot Update this PR to include a sample for the newly documented MarkerSize property.

Use the sample added in IgniteUI/igniteui-xplat-examples#1013, specifically: samples/charts/data-chart/scatter-marker-options.json

Add the sample to the Marker Size section so the documentation shows a working example based on scatter-marker-options.json. This sample includes the interactive Marker Size editor and demonstrates markerSize on scatter series, which matches the property being documented here.

Please keep the documentation aligned with the sample implementation from the examples PR.

[Copilot]

@copilot Update this PR to include a sample for the newly documented MarkerSize property.

Use the sample added in IgniteUI/igniteui-xplat-examples#1013, specifically: samples/charts/data-chart/scat...

Added the scatter-marker-options sample to the Marker Size section in all three language files (en, jp, kr) in commit dc8ed8a. The sample is placed after the code examples and before the BubbleSeries caveat note.

[ChronosSF]

@copilot resolve the merge conflicts in this pull request

[Copilot]

@copilot resolve the merge conflicts in this pull request

Resolved in commit e6ff350. The conflicts arose from vnext adding a new "Checkmark Marker Type" section while our branch added "Marker Size". Both sections are now preserved, and mentionedTypes and API references from both branches have been merged.