differentiate between math operators

[lorenzwalthert]

Allow the user to set spacing separately for

• + and -
• / and *
• ^

etc.

[krlmlr]

Reference: #79 (comment)

[lorenzwalthert]

Should this be a separate option or go under strict? I suggest creating a new argument math_token_spacing that takes a list that has two lists in it: One containing the tokens where we want 1 space before/after it and one that contains the tokens that should have no spacing before/after them. We can use a helper function to create this list like that

specify_math_token_spacing(zero = c("'*'", "'/'"), one = c(...)

Tokens that are not mentioned in zero or one will have space around it, since that the tidyverse style guide encourages.

[lorenzwalthert]

Note that the proposed API is similar to the one proposed in #217 where we have
reindention = specify_reindention(...)

[lorenzwalthert]

Closed with #221.