Documentation and CLI Tidying

[caronc]

Description:

Related issue (if applicable): n/a

Cleaned some documentation up and CLI output

Checklist

• The code change is tested and works locally.
• There is no commented out code in this PR.
• No lint errors (use flake8)
• 100% test coverage

Testing

Anyone can help test this source code as follows:

# Create a virtual environment to work in as follows:
python3 -m venv apprise

# Change into our new directory
cd apprise

# Activate our virtual environment
source bin/activate

# Install the branch
pip install git+https://github.com/caronc/apprise.git@apprise-cli-output-tidy

# Test out the changes with the following command:
apprise --help

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.35%. Comparing base (9addff8) to head (b2e0b2a).
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #1187   +/-   ##
=======================================
  Coverage   99.35%   99.35%           
=======================================
  Files         146      146           
  Lines       20179    20186    +7     
  Branches     3967     3967           
=======================================
+ Hits        20048    20055    +7     
  Misses        121      121           
  Partials       10       10           

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