Style: Partially apply clang-tidy's `cppcoreguidelines-pro-type-member-init`

Didn't commit all the changes where it wants to initialize a struct
with `{}`. Should be reviewed in a separate PR.

Option `IgnoreArrays` enabled for now to be conservative, can be
disabled to see if it proposes more useful changes.

Also fixed manually a handful of other missing initializations / moved
some from constructors.

1 files changed, 1 insertions, 1 deletions

diff --git a/editor/progress_dialog.h b/editor/progress_dialog.h
index f395750165..23a77ea201 100644
--- a/editor/progress_dialog.h
+++ b/editor/progress_dialog.h
@@ -85,7 +85,7 @@ class ProgressDialog : public PopupPanel {
 	void _popup();
 
 	void _cancel_pressed();
-	bool cancelled;
+	bool cancelled = false;
 
 protected:
 	void _notification(int p_what);