Enhance Line Chart Examples with Interactive Tooltip Display for Basic and Smoothed Charts

[Manahil-Afzal]

The current Basic Line Chart and Smoothed Line Chart examples display static data but do not provide interactivity to view individual data points on click or hover.

Before:
. Basic Line Chart: [150, 230, 224, 218, 135, 147, 260]
.Smoothed Line Chart: [820, 932, 901, 934, 1290, 1330, 1320]

Problem:
Users cannot easily see the corresponding category (X-axis) and value (Y-axis) for each point on the line.

Suggested Enhancement:
-> Add tooltip with formatter to show the category and value when hovering or clicking on a point.
-> Apply this enhancement to both the basic and smoothed line chart examples.
-> This will make the examples more interactive and informative for developers learning ECharts.

[Manahil-Afzal]

Planning to add tooltips to Basic and Smoothed Line Charts so users can view category and value on hover/click. Will submit a PR with the changes.