Make quotation usage consistent

[brishtibheja]

I suggest we replace all instances of single quotations with either double quotes or italics. In some cases, single quotes are being used for emphasis where using italics might be better suited. In other cases, double quotes are better suited as this is what we use most of the time.

#231

[dae]

No objections to this, if it's done carefully (e.g. don't accidentally change apostrophes).