Bug fix to pseudocode for spaCy tokenizer

[giannisdaras]

Description

Types of change

This pull request is a bug fix to the pseudocode provided in the website of spaCy docs for implementing/customizing spacy tokenizer.
The pseudocode provided here slices wrongly the substring when a suffix is spotted. In order to make it write, the following lines of code

suffixes.append(substring[split:])
substring = substring[:split]

should be changed to:

suffixes.append(substring[-split:])
substring = substring[:-split]

Checklist

• I have submitted the spaCy Contributor Agreement.
• I ran the tests, and all new and existing tests passed.
• My changes don't require a change to the documentation, or if they do, I've added all required information.

[ines]

Ah, you're right – thanks a lot! 👍