RK-A

In the C-API book, I have seen some cases where the KPs are wrongly starting with numbers in words like "one positional argument". We need to make sure that such cases are removed. POS tags can be used for the same. Would be nice to implement it in the generate_candidates function along with other POS tag filters.

NOTE: Additional checks can be done to ensure that the above-mentioned KP is removed only when the header variant doesn't start with a number.