Update intro_to_gps.py

[neel-maniar]

A small typo: $\mathbf{X}\in \mathbf{X}$ was updated to $\mathbf{X}\in\mathcal{X}$

Type of changes

• Bug fix
• New feature
• Documentation / docstrings
• Tests
• Other

Checklist

• I've formatted the new code by running poetry run pre-commit run --all-files --show-diff-on-failure before committing.
• I've added tests for new code.
• I've added docstrings for the new code.

Description

A small typo in the intro_to_gps.py file: $\mathbf{X}\in \mathbf{X}$ was updated to $\mathbf{X}\in\mathcal{X}$.

Issue Number: N/A

[github-actions]

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[thomaspinder]

Thanks @neel-maniar !