[Enhancement] explain LOOK_AND_FEEL_TABLE dictionary entry values in docs

查看 Cookbook 中的“修改主题 & 添加自定义主题”和“示例 - 添加自定义颜色主题”部分，以及现有的主题文档。记录 LOOK_AND_FEEL_TABLE 条目的含义和可接受的值，包括 ACCENT 键，并更新示例，使其反映可用的条目。

Type of Issue (Enhancement, Error, Bug, Question)

Enhancement

Environment

Operating System

Windows version ('7', '6.1.7601', 'SP1', 'Multiprocessor Free')

PySimpleGUI Port (tkinter, Qt, Wx, Web)

tkinter

Versions

Python version (sg.sys.version)

3.8.6 (tags/v3.8.6:db45529, Sep 23 2020, 15:52:53) [MSC v.1927 64 bit (AMD64)]

PySimpleGUI Version (sg.__version__)

4.61.0.196

GUI Version (tkinter (sg.tclversion_detailed), PySide2, WxPython, Remi)

8.6.9

Your Experience In Months or Years (optional)

2 Years Python programming experience
2 Years Programming experience overall
No Have used another Python GUI Framework? (tkinter, Qt, etc) (yes/no is fine)

Troubleshooting

These items may solve your problem. Please check those you've done by changing - [ ] to - [X]

• Searched main docs for your problem www.PySimpleGUI.org
• Looked for Demo Programs that are similar to your goal. It is recommend you use the Demo Browser! Demos.PySimpleGUI.org
• If not tkinter - looked for Demo Programs for specific port
• For non tkinter - Looked at readme for your specific port if not PySimpleGUI (Qt, WX, Remi)
• Run your program outside of your debugger (from a command line)
• Searched through Issues (open and closed) to see if already reported Issues.PySimpleGUI.org
• Upgraded to the latest official release of PySimpleGUI on PyPI
• Tried using the PySimpleGUI.py file on GitHub. Your problem may have already been fixed but not released

Detailed Description

The docs contain no explanation of the values you use to set your own themes, which should mimic the structure and keys of the other themes.
example:
"Material1": {
"BACKGROUND": "#E3F2FD",
"TEXT": "#000000",
"INPUT": "#86A8FF",
"TEXT_INPUT": "#000000",
"SCROLL": "#86A8FF",
"BUTTON": ("#FFFFFF", "#5079D3"),
"PROGRESS": DEFAULT_PROGRESS_BAR_COMPUTE,
"BORDER": 0,
"SLIDER_DEPTH": 0,
"PROGRESS_DEPTH": 0,
"ACCENT1": "#FF0266",
"ACCENT2": "#FF5C93",
"ACCENT3": "#C5003C",
}
Additionally, the examples shown in the Cookbook (Making Changes to Themes & Adding Your Own Themes; Recipe - Adding Your Own Color Theme) don't feature these "ACCENT" keys.

Code To Duplicate

# Paste your code here

Screenshot, Sketch, or Drawing

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someone recommended me to this a few years ago