turn off automated documentation for all equation.gms files

[LaviniaBaumstark]

Purpose of this PR

turn off automated documentation for all equation.gms files and acticate it only for selected equations

Type of change

• [x] Refactoring

Checklist:

• [x] My code follows the coding etiquette
• [x] I performed a self-review of my own code
• [x] I explained my changes within the PR, particularly in hard-to-understand areas
• [x] All automated model tests pass (FAIL 0 in the output of make test)

Further information (optional):

• Test runs are here:
• Comparison of results (what changes by this PR?):