Ignore editor.insertSpaces within strings

[edwardgalligan]

Related issues

After searching existing issues, I found two open issues, which are closely related, but different. Including links for reference purposes:

• Add support for mixed tab/spaces indentation #5394
• Request: Support different indentation modes for different syntaxes in same file #46287

Feature request

Tabs have three uses in code files:

1. Indentation at the beginning of lines - people often prefer to use spaces here
2. Indentation between keys and values or around assignment operators - people often prefer to use spaces here
3. When a literal tab character is required within a string - this should always be a tab and never converted to spaces.

Currently, the 3rd use-case is difficult/impossible to handle easily in VSCode when editor.insertSpaces is set to true.

The most common place I've encountered this is for RegEx strings in BSD sed, which does not support GNU's non-standard \t notation for tabs.