[Feature] Separate commands for increasing and decreasing blockquote

[huyz]

Could you implement the same functionality as https://github.com/czottmann/obsidian-blockquote-levels with two separate commands so that there's no ambiguity?

I explained my rationale here: yzhang-gh/vscode-markdown#811 (comment)

[Sean10]

You're right. I'll change it later

[Sean10]

publish v0.3.0 with increase and decrease quote. But I don't set default keybinding

[huyz]

@Sean10 Works great, thank you!