whitespace around = in kwargs

[ranocha]

For consistency with Trixi.jl

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Comparison is base (0e8161a) 93.65% compared to head (22e568e) 93.65%. Report is 2 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #7 +/- ## ======================================= Coverage 93.65% 93.65% ======================================= Files 4 4 Lines 63 63 ======================================= Hits 59 59 Misses 4 4 ```

:umbrella: View full report in Codecov by Sentry.
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[github-actions[bot]]

Pull Request Test Coverage Report for Build 7698756899

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 93.651%

---

Totals
Change from base Build 7698753991:	0.0%
Covered Lines:	59
Relevant Lines:	63

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💛 - Coveralls

[sloede]

@ranocha sorry, I might have re-re-re-formatted during merge conflict resolution... can you please format once more?

[ranocha]

Thanks