proper e-notation equation table

[JohnnyDoorn]

Fix https://github.com/jasp-stats/external-issues/issues/7

[Copilot]

Pull request overview

Updates regression equation coefficient formatting to handle scientific notation more appropriately (issue #7), and adjusts example-based tests/snapshots accordingly.

Changes:

• Format regression equation coefficients via a new helper instead of round().
• Split the “Exam Anxiety” example test to target specific analyses and add a regression test.
• Add new SVG snapshot outputs for the Titanic example.

Reviewed changes

Copilot reviewed 2 out of 5 changed files in this pull request and generated 3 comments.

File	Description
tests/testthat/test-example-Exam Anxiety.R	Selects specific analyses from the example file and adds coverage for RegressionLinear outputs.
tests/testthat/_snaps/example-Titanic/analysis-1-figure-3-jaspcolumn3.new.svg	Adds a new/updated snapshot output for Titanic example figure 3.
tests/testthat/_snaps/example-Titanic/analysis-1-figure-2-jaspcolumn1.new.svg	Adds a new/updated snapshot output for Titanic example figure 2.
R/regressionlinear.R	Introduces .formatCoefEquation() and uses it for equation-table coefficient formatting.

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[juliuspfadt]

Nice! issue is fixed. after the tests, this can be merged :)