Clarify Experiment Steps and Other Requirements in Documentation

Problem
The current FuzzBench documentation does not clearly indicate whether experiment name requirements (e.g., lowercase letters, numbers, hyphens, length restrictions, and avoiding underscores) are enforced by run_experiment.py or elsewhere in the system. This ambiguity can confuse users who may be uncertain whether these constraints are mandatory or merely recommended.

Proposed Solution
I am raising a pull request to propose an update to the documentation. The change will explicitly clarify that `\gcbrun` and/or `run_experiment.py` does not enforce these experiment name requirements, though other parts of the system (e.g., CI/CD pipelines or maintainers’ review processes) may enforce them. This update will also emphasize the importance of following the naming conventions to prevent issues during experiment submission.

I will comment here once the PR once ready.