[docs] removed -s flag from documentation

[boyestrous]

Website documentation fixes:

1. -s does not exist for stocks/options, must use --source

2. per data_sources_default.json, fixed incorrect references to sources in the options module:
   -tr must be full name: tradier
   -ce must be full name: chartexchange

3. Whitespace removal (end of line, etc.)

Functions and --help information are already correct, we just needed to correct the website docs

Description

• Summary of the change / bug fix.
• Link # issue, if applicable. [Bug] Short version of source flag ('-s') cannot be interpreted #2378
• Screenshot of the feature or the bug before/after fix, if applicable.
• Relevant motivation and context.
  • docs don't match actual behavior (difficult for new users)
  • Tradier no longer offers developer-only licenses, brokerage accounts are required, so Yahoo finance may be a preference
• List any dependencies that are required for this change.
  • none

How has this been tested?

• Please describe the tests that you ran to verify your changes.
  • viewed the relevant markdown files in github after pushing to my fork
• Provide instructions so we can reproduce.
• Please also list any relevant details for your test configuration.

Checklist:

• Update our Hugo documentation following these guidelines.
• Update our tests following these guidelines.
• Make sure you are following our CONTRIBUTING guidelines.
• If a feature was added make sure to add it to the corresponding scripts file.

Others

• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• My code passes all the checks pylint, flake8, black, ... To speed up development you should run pre-commit install.
• New and existing unit tests pass locally with my changes. You can test this locally using pytest tests/....

[DidierRLopes]

Nice one! Thanks! 😀