drivers/periph/i2c: Replace LaTeX formula with static SVG file in documentation

[crasbe]

Contribution description

I started adding the MathJax support as discussed in #21490 but then I realized that it is somewhat stupid to add such a big dependency for static LaTeX formulas and instead asked ChatGPT to generate SVG files from said LaTeX formulas.

Also I changed the comments from // to /* */ to stay consistent with our Coding Convention.
This breaks things when not inside a doc.md file.

Testing procedure

Check the generated Doxygen documentation in the subpage group__drivers__periph__i2c.html.

Issues/PRs references

Fixes #21490.
Depends on (and currently includes) #21372.

[riot-ci]

Murdock results

✔️ PASSED

1cd37aa drivers/periph/i2c: replace LaTeX eqn. with SVG in doc

Success	Failures	Total	Runtime
1	0	1	02m:12s

Artifacts

• Documentation preview

[crasbe]

This is what it looks like with Doxygen 1.15.0:

This is what it looks like with Doxygen 1.13.2 (which currently generates our Website):

This is what it looks like with Doxygen 1.9.1 (which is still used by Murdock) with enforced Dark Mode:

This is what it looks like with Doxygen 1.9.1 (which is still used by Murdock) without enforced Dark Mode:

[maribu]

I have seen Github showing even complex SVG images, so I would assume that the SVG source is not valid syntax.

[AnnsAnns]

RE: SVG problem

I've encountered that a few times during my bachelor thesis so far. The trick is to re-export the SVG using inkscape because SVG rendering is cursed weird.

[AnnsAnns]

Oops, did not want to approve with this but I guess the approval still counts once the SVG is fixed 😅

[AnnsAnns]

Nevermind, no pre-approval for you 🤨

[kfessel]

Why not just get rid of the math rendering and go for somethin code style

R_min = (V_DD - V_OL) / I_OL
R_max = t_r / (0.8473 * C_b)
Where: 
    V_DD : Supply voltage
    V_OL = Low level voltage upper limit 
    I_OL =  Low level output current,
    t_r =\Signal rise time,
    C_b = Bus capacitance

this would make the formular readable in the comment (and not only in doxygen / html rendering)

the latex-math is barely readable in the c-comment and the svg even less

[kfessel]

KISS

Suggested change

	* @image html periph_i2c_bus_equations.svg
	* R_min = (V_DD - V_OL) / I_OL
	* R_max = t_r / (0.8473 * C_b)
	* Where:
	* V_DD: Supply voltage
	* V_OL: Low level voltage upper limit
	* I_OL: Low level output current,
	* t_r: Signal rise time,
	* C_b: Bus capacitance

[crasbe]

I like the utilitarian approach, but the SVG image is more beautifuller :)

[AnnsAnns]

Squashy squash pls

[crasbe]

Thank you for the review and the modified SVG :)