Typos and minor parameter readability issues in README

[Toefinder]

1. There are some minor typos in the README file, such as "content mode" instead of "contest mode", among others.

2. The parameters are also slightly difficult to distinguish when written in a single style like this:

   Do to a simple search, the q parameter is used to search for a specific word or phrase

   I suggest putting all the parameters in code quotes, such as

   Do to a simple search, the q parameter is used to search for a specific word or phrase

   and this style can be applied into the parameter table as well. (by the way, "Do to" is also a typo)

   Parameter	Description	Default	Accepted Values
   q	Search term.	N/A	String / Quoted String for phrases

If this is deemed to be useful, I can help to edit the README. I just started with this API, found it great, and would like to contribute a little bit. :smiley: