Per-Syntax settings

[spywhere]

TL;DR: Add settings support for per-syntax or improve the Markdown syntax settings recognition.

Problems:
In my project development, I usually works across different file types. Each of them is work a bit different than the another.

Let say I have a .js (JavaScript) file and some .md (Markdown) file. When I works with .js file, I want to trim of the whitespace at the end of each line while when I works with .md file, I want the VSCode to keep the whitespace at the end of line as-is () since the markdown syntax use double-spaces at the end of line to indicate line break. When I enabled files.trimTrailingWhitespace, I cannot save the file without remove these trailing whitespace on .md file and that is annoying to me.

Also, this is just a simple usage example of this feature. There are many cases that this feature would solve them easily.

Possible Solutions:

• Implement per-syntax settings so each file type can be configured differently (preferred).
• Implement the "smart settings" where if you works with (let says) Markdown file and there are double-spaces at the end of line (or just any language feature at similar to this) with files.trimTrailingWhitespace turn on, VSCode will not trim those lines.

[joaomoreno]

cc @chrisdias @egamma @waderyan @seanmcbreen @bpasero @alexandrudima

[egamma]

@spywhere can you pls try vscode-editorconfig extension and see whether it covers your needs.

[spywhere]

@egamma That's cover my need. However, I didn't see it working on my project. I hope I'm not configured it wrong.

[bpasero]

#1587