Brace yourself: one is the word "if" and the other is the word "if" but this time spelled with a yogh (with the yogh probably corresponding to a "y" sound, or the IPA /j/). They're both common Middle English spellings for the same word. There's no deeper meaning behind it.
What does one encounter reading the “Wycliffe Bible”? [...] Spelling and verb forms that are not standardized, in part because they were phonetic to different dialects. For example, the word “saw” is spelled a dozen different ways (even differently within the same sentence), and differently for singular and plural nouns (similarly, the word “say”); “have take” and “have taken” are found in the same sentence, as are “had know” and “had known”; and so forth.
Introduction to Wycliffe's Bible by
Terence P. Noble
This is just how Middle English was. Chaucer, a contemporary of Wycliffe's, is also noted for inconsistencies in spelling:
Such was the pace of continuous change to the language at this time, that different forms of words were often used interchangeably, even by the same author, and this flexibility (or inconsistency) in spelling is quite noticeable in Chaucer’s work (e.g. yeer and yere, doughtren and doughtres, etc). However, it should be noted that, because Chaucer’s work was copied by several different scribes, and we have no original in Chaucer’s own hand, different manuscripts have different spellings, none of which are definitive (e.g. the same word is variously rendered as site, sighte, syth, sigh and cite in different manuscripts).
The History of English > Middle English
(The more you read from this time period, the more you notice this.)
This might seem pretty foreign (because it is: there's not much that comes even close to that in written English anymore), but it might help to think of spoken English. Remember, there are some people who pronounce caramel both ways, for no reason, practically within the same breath (as an example; there might be some word that's the same for you too).