Week Start - Highlights the first candle of the week

Some users asked in PM about a script that highlights the start of the week. Consequently, I decided to publish it open for anyone finding it useful.

Furthermore, I will update the script soon with more useful features and customisation options.

版本注释:

- The script can now highlight the start of any selected day of the week
- Can highlight the first candle of the month
- Added feature to highlight with a line instead of background

版本注释:

- The script can now highlight the start of any selected day of the week
- Can highlight the first candle of the month
- Added feature to highlight with a line instead of background