zig fmt: fix tracking of applied indentation

lib/std/zig/Ast/Render.zig

@@ -3883,8 +3883,8 @@ const AutoIndentingStream = struct {
     /// Writes ' ' bytes if the current line is empty
     fn applyIndent(ais: *AutoIndentingStream) Error!void {
         const current_indent = ais.currentIndent();
-        if (ais.current_line_empty and current_indent > 0) {
-            if (ais.disabled_offset == null) {
+        if (ais.current_line_empty) {
+            if (current_indent > 0 and ais.disabled_offset == null) {
                 try ais.underlying_writer.splatByteAll(' ', current_indent);
             }
             ais.applied_indent = current_indent;

lib/std/zig/parser_test.zig

@@ -6676,6 +6676,23 @@ test "zig fmt: doc comments on fn parameters" {
     );
 }
 
+test "zig fmt: proper tracking of indentation" {
+    try testCanonical(
+        \\const a = {
+        \\    {}
+        \\};
+        \\const b = if (x) {};
+        \\const c = .{
+        \\    {
+        \\        {}
+        \\    } //
+        \\    ,
+        \\    if (x) {},
+        \\};
+        \\
+    );
+}
+
 test "zig fmt: canonicalize stray backslashes in identifiers" {
     try testTransform(
         \\const @"\x" = undefined;