[DOCS] usage of context

### Documentation Type

Missing documentation (feature not documented)

### Documentation Location

_No response_

### Section/Topic

/context

### Current Documentation

When enter /context at vs code,
The result is shows in 2ways

1. Pop up
Pop up and show brief usage with bar graph
2. Text
Show detail usage each items in text

I cannot determine whether shows text or Pop up

I just tried '/context text' it show most of result in text but it does not descripted in document.

Anybody know exactly valid subcommittee or arguments?

### What's Wrong or Missing?

.

### Suggested Improvement

.

### Impact

High - Prevents users from using a feature

### Additional Context

.

Start at the /context CLI command and verify the behavior shown in the issue for /context and /context text. Document the available output modes and valid arguments so users can determine when the popup or detailed text output appears; done means the command usage is unambiguous.

由索引模型根据 Issue 内容生成。