terminal: OSC7 with empty URL resets the pwd to nil

When an empty string is given to OSC7, the pwd is reset to nil (as if
the terminal never received a pwd report to begin with). This is
analogous to how OSC0/2 reset the title to nil when given an empty
string.

This is practically useful for macOS because it allows our proxy icon to
also be reset instead of being stuck on the last known path.

This breaks from any known terminal behavior. As far as I can find, this
is totally unspecified so we're somewhat free to do what we want. I
don't think any terminal programs depend on this behavior, so I think
it's safe to change it.

src/terminal/osc.zig

@@ -641,7 +641,7 @@ pub const Parser = struct {
             .@"7" => switch (c) {
                 ';' => {
                     self.command = .{ .report_pwd = .{ .value = "" } };
-
+                    self.complete = true;
                     self.state = .string;
                     self.temp_state = .{ .str = &self.command.report_pwd.value };
                     self.buf_start = self.buf_idx;
@@ -1382,6 +1382,18 @@ test "OSC: report pwd" {
     try testing.expect(std.mem.eql(u8, "file:///tmp/example", cmd.report_pwd.value));
 }
 
+test "OSC: report pwd empty" {
+    const testing = std.testing;
+
+    var p: Parser = .{};
+
+    const input = "7;";
+    for (input) |ch| p.next(ch);
+    const cmd = p.end(null).?;
+    try testing.expect(cmd == .report_pwd);
+    try testing.expect(std.mem.eql(u8, "", cmd.report_pwd.value));
+}
+
 test "OSC: pointer cursor" {
     const testing = std.testing;
 
@@ -1395,17 +1407,6 @@ test "OSC: pointer cursor" {
     try testing.expect(std.mem.eql(u8, "pointer", cmd.mouse_shape.value));
 }
 
-test "OSC: report pwd empty" {
-    const testing = std.testing;
-
-    var p: Parser = .{};
-
-    const input = "7;";
-    for (input) |ch| p.next(ch);
-
-    try testing.expect(p.end(null) == null);
-}
-
 test "OSC: longer than buffer" {
     const testing = std.testing;