Add ability to move text cursor by words

[chiroptical]

Currently, text cursors only move one character at a time. In this PR, I added functions which allow you to move more than one character at a time. For example, using pseudo code to represent a cursor as a single string where ^ indicates the position of the cursor,

example	result
beginWord "hell^o"	"^hello"
endWord "hell^o"	"hello^"
nextWord "hel^lo world"	"hello ^world"
prevWord "hello w^orld"	"hello^ world"

TODO

• Run ormolu (I previously ran hindent because I saw .hindent.yaml)
• Run hlint

[NorfairKing]

Lovely! Let's discuss this on stream!