docs: Mention partial vs. exact match in ignoreErrors docs

[kamilogorek]

Closes #1013

[MaxBittker]

good point, except maybe this implies that regexp always are exact matches? obviously your example shows ^$ but it could be misleading if someone misses that

[benvinegar]

good point, except maybe this implies that regexp always are exact matches?

We could elaborate, but I think the example is sufficiently clear. Not a big deal; this is an objective improvement.

[kamilogorek]

I think that if someone is brave enough to use RegExp, then they know what ^$ means :D