fix issues with RDoc generation

[davetron5000]

Reading the RDoc and noticed a few things weren't generating correctly.

• RDoc supports * to bold something, but only at the word level. For more than one word, you have to use <b> tags
• There was a dangling <tt> unclosed
• For inline code, the code must be indented or it won't format as code

[davetron5000]

I realize technically one space would suffice, but four seemed better for reading the docs inline so that the indentation is clearly intentional. LMK if it should be done differently.

[radar]

I think this will work how you want it to :)