## What's Changed
* Check instructions length before setting option value by
@jamiebenstead in
#1196


**Full Changelog**:
v0.29.0...v0.29.1

## What's Changed?

- Fixed the mode on the `pyodide` side - it was always using `w` rather
than the mode provided in the code
- Fixed the file write append mode on the frontend - it was incorrectly
adding a newline character before anything was appended.

closes #1202

This PR is very much WIP
Although these changes fix the original bug, they introduce an issue
with the `p5` canvas that needs investigating before this can go out.

Steps to reproduce:
1. Run a basic `p5` program
2. Delete that code and run `print("hello world")`
3. Run the basic `p5` program again

Expected behaviour: Output from the `p5` program is displayed in the
visual output tab
Actual behaviour: The visual output tab is rendered, but no output is
visible

closes
RaspberryPiFoundation/digital-editor-issues#137

### Added
- `editor-projectLoadFailed` custom event that fires when a project
completely fails to load (#1201)
- Added runnerBeingLoaded state to prevent race condition overwrites
(#1205)

### Fixed
- Bugs in append mode for writing to files in python (#1200)
- `turtle` bug that did not display output on first code run (#1203)