Improve documentation

[Rowlando13]

Pick a section of the docs and improve it. Look for

• Typos
• inconsistencies - somewhere else in the docs it says something different

Or improve

• coverage of click's behaviors
• clarity of language
• clarity of examples - each example should clearly and simply show the behavior explained

Post on this issue which section(1 file at a time please) you are taking

[developer-rpai]

@Rowlando13 I've found few duplicates and problems with clarification of arguments, in General Reference section. Can you please assign me this issue, as I would like to cover more sections once initial iterations are approved

[Rowlando13]

The general reference section is 20 plus files. Lets start with one. Which one or would you like to work on?

[AmoghDeshmukh]

Hello, I want to contribute on this issue. Should I proceed with it?

[developer-rpai]

The general reference section is 20 plus files. Lets start with one. Which one or would you like to work on?

I found a typo and a logical inconsistency in documentation pages for src/click/core.py and src/click/decorators.py modules . Specifically in options and arguments CLI parameters.
Additionally, can you please clear this confusion?

1. Arguments class states that arguments are required by default when no default value is provided (and nargs > 0) and arguments become optional when a default value is set. But the note on required arguments (in docs/arguments.rst) states the following:
   "It is possible to make an argument required by setting required=True. It is not recommended since we think command line tools should gracefully degrade into becoming no ops. "

• this implies that arguments are not required by default.