emitDbgNode

fn emitDbgNode(gz: *GenZir, node: Ast.Node.Index) !void {
    // The instruction emitted here is for debugging runtime code.
    // If the current block will be evaluated only during semantic analysis
    // then no dbg_stmt ZIR instruction is needed.
    if (gz.is_comptime) return;
    const astgen = gz.astgen;
    astgen.advanceSourceCursorToNode(node);
    const line = astgen.source_line - gz.decl_line;
    const column = astgen.source_column;
    try emitDbgStmt(gz, .{ line, column });
}