Fixed about_blocks.rb to pass tests

Learned about:
* yield and methods that can take blocks,
* blocks can be defined with curly brackets or do-end,
* blocks can take arguments,
* methods can call yield multiple times.

[#65851776]
Fixed about_blocks.rb to pass tests

Learned about:
* methods can see if they have been called with a block,
* block can affect variables in the code where they are created,
* blocks can be assigned to variables,
* and passed to methods as arguments,

[#65851776]
Merge pull request #17 from mkreyman/65851776_about_blocks_master

about blocks master

[Delivers #65851776]