🖊️ #5910 replace echo with answer interpolation

[koenelsdijk]

@jpelay
This is a partial fix, but here is a draft PR.
Initially, it contains the language transpilation of the feature.
What still needs to be done, afaik:

• fix code validation

• fix syntax highlighting in editor

• description, explanation in adventures (ask levels 1 & 2), docs (@MarleenGilsing ;))

• Fixes 🖊️change 'echo' into a variable #5910

  • Allows for the use of answer as a translatable keyword to use the variable stored in the ask command
  • The value can be interpolated in strings in the print and ask commands
  • Initially implemented in level 1

How to test

Go to http://localhost:8080/hedy/1#ask_command
Run this code:

print Hello! This is about answer. 
ask What is your name?
print Hello answer!
ask How old are you, answer?
print Wow, answer is very old!

Expected output:

Hello! This is about answer. 
What is your name? # type in 'Hedy'
Hello Hedy!
How old are you, Hedy? # type '42'
Wow, 42 is very old!

[jpelay]

Hello, @koenelsdijk! Thank you for the PR, @MarleenGilsing tells me you can no longer continue working on the feature and we are going to take it from here. But I have a question, can you upload the changes to the transpiler? I'm not seeing them on the changed files of the PR 🤔

[koenelsdijk]

Hi @jpelay, sorry for the slow response.
The transpiler changes are already here, in hedy/__init__.py in class ConvertToPython_1(ConvertToPython): https://github.com/hedyorg/hedy/pull/6491/changes#diff-fe992300672e02f245ac6f99b644631655c0f13db2c3e45f15652444ebc26850.
Or did you mean something else?