Fixes test_a_pattern_is_a_regular_expression

* I learned that RegExp are a class and that they
  are usually contained within two forward slashes
* Learned that regular expressions can search a
  string for a match using the RegExp within [ ]
  after a string
* Learned that if there isn't a match for a
  regular expression, it will return nil
* I learned that a question mark after an atom
  means that that atom is optional to the match
* I learned that a plus indicates that the last
  atom can be matched one or more times
* I also learned that the RegExp will match the
  larges expression available, it seems
* I learned that an asterisk will match zero or
  more times, but will fail to match if the atom
  doesn't exist
* The repetition operators are greedy because they
  will match the largest pattern they can find

[#65851412]
Fixes test_the_left_most_match_wins

* I learned that RegExp will begin matching from
  left-to-right
* I learned that you can use [ ] to define a set
  through which to match from
* I learned that you can use \d to specify a match
  for any digit from 0-9
* I learned that character classes within [ ]
  can include ranges like 0-9
* I learned that \s can be used to match
  whitespace
* I learned that you can use \w to match for a
  word rather than use a long character class
  with ranges

[#65851412]
Fixes test_period_is_a_shortcut_for_any_non
   _newline_character

* I learned that a period will match any
  non-newline character
* I learned that by using a ^ character within a
  character class, you can tell it to not match
  characters within that class
* I learned that capitalizing shortcut character
  classes means to negate them
* I learned that a \A anchors the match to the
  start of the string
* If a \A can't match to the start of a string,
  then it will return nil
* I learned that \z anchors to the end of a string
* If \z can't find a match at the end of a string,
  then it will return nil
* I learned that the caret "^" character anchors
  to the beginning of lines

[#65851412]
Fixes test_dollar_sign_anchors_to_the_end_of_lines

* I learned that the $ character anchors to the
  end of lines
* I learned that \b anchors to a word boundary,
  which seems to be a zero-width position between
  a word-character and a non-word character
* I learned that ( ), group contents, unlike [ ]
  which are character classes
* I learned that once you've grouped content, you
  can then access it by calling it's "index
  number" so to speak
* I learned that you can access items captured
  with parenthesis ( ) in a variables like $1 and
  $2
* I learned that you can use a vertical pipe
  character to mean "or." This is useful for
  choosing between items where you can't specify
  a range (like numbers)

[#65851412]
Fixes test_scan_is_like_find_all

* I learned that the .scan method can be used on
  a string with a regular expression match to find
  every match of the regular expression, not just
  the first
* Not sure how .sub is used in this instance
* Not sure what .gsub and .sub are replacing. I'll
  have to ask this in class

[#65851412]