Grammar, spelling on README; Codeblock formatting [ci skip]

- LinkedIn item missing link to issue, rendering the rest of the
  line as broken link
- Codeblocks in lists need to indent four spaces for each nesting
  under bullet list item
- Fix some capitalisation in certain words
- Some paragraphs work better with multiple sentences instead
  of using many commas
Merge pull request #317 from randomecho/copyedit-readme

Copyedits on README - Codeblock formatting, grammar and fixing a link to issue