Bash support in embedded code blocks of *.nix files

[jnoortheen]

• Embedded language support for Bash.

[ian-h-chamberlain]

For inspiration, tree-sitter-nix seems to use various prefixes to decide whether a string should be injected as bash:

• /* bash */ comment beforehand (also supports e.g. /* python */ etc. but not sure if this is feasible with LSP / tmLanguage)
• writeShellScript, runCommand, writeShellApplication
• various phases / hooks like configurePhase, buildPhase etc.

Supporting the /* bash */ comments would be nice if possible, since this allows for highlighting scripts in let bindings and arbitrary function args that might not be recognized automatically, while still leaving other multi-line strings as plain strings.

Edit: it may also be feasible to use request forwarding to support arbitrary language servers, so VSCode could fall back to something like bash-lsp for highlighting/completion etc