Find & Replace: option to scope search to prose or code blocks in `.qmd` files

Enhancement Request Summary

Add filter options to the editor Find & Replace panel that let users restrict matches to either prose regions or code-block regions in .qmd documents.

Context

I noticed this gap while using Find & Replace in Positron. However, since the feature would require awareness of Quarto document structure — distinguishing prose regions from fenced code blocks — I'm filing it here on the assumption that it belongs in the Quarto extension rather than in Positron itself. Happy to be redirected if that reasoning is wrong.

Motivation

In mixed-format documents like .qmd, many terms appear in both prose and code with intentionally different formatting. For example:

• The desired markdown formatting for a book title like Great Expectations might be italics in prose but unformatted in code (e.g., str_detect(title, "Great Expectations")
• A function name like filter may need to be renamed in code without touching narrative references to "filtering"

The current find/replace is document-wide, making these edits either manual or reliant on complex regular expressions that approximate zone detection.

Proposed behaviour

Add a new toggle or dropdown to the in-editor Find/Replace widget and/or the global search panel when the active file is a .qmd, with three modes:

Implementation notes

The Quarto extension already parses the document structure to support cell execution, folding, and diagnostics, so the zone boundaries are available. The find/replace scope could be implemented by:

1. Restricting the set of ranges passed to the editor's find implementation, or
2. Post-filtering results to exclude ranges that fall in the wrong zone. This could be delivered initially for the in-editor Cmd/Ctrl+F widget; workspace-wide search (sidebar) is a secondary concern.

Related

Source editor priorities for 2026: #897
VS Code does not support this natively; this would be a Quarto-extension-level feature

Start by locating the Quarto extension's existing document-structure parsing used for cell execution, folding, and diagnostics, along with the in-editor find implementation. Determine how scoped ranges could support .qmd prose, code, and all modes; done means the in-editor Find/Replace behavior matches the three specified scopes, with workspace-wide search treated as secondary.