fix(docs): correct example and visualization docs

[favilances]

This PR fixes documentation inconsistencies in the examples and visualization docs.

Changes:

• Corrects the Example 11 script name in the README from 11_gemex_tabular_plots.py to 11_alternative_plots_tabular.py.
• Updates the Example 11 script docstring and usage examples to match the actual filename.
• Updates the README visualization count from 13 to 14 and adds the missing dependence plot documentation.
• Clarifies that Example 14 showcases all applicable tabular plot types, adds the dependence plot to that showcase, and notes that image_trio is image-only.
• Removes development comments left in gemex/viz/plots.py.

Checks:

• python -m py_compile examples/11_alternative_plots_tabular.py examples/14_all_plots_showcase.py gemex/viz/plots.py
• git diff --check HEAD~2..HEAD

Both checks passed with no issues.