Added docs

pkg/yqlib/doc/operators/headers/divide.md

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+# Divide
+
+Divide behaves differently according to the type of the LHS:
+* strings: split by the divider
+* number: arithmetic division

pkg/yqlib/doc/operators/headers/filter.md

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+# Filter
+
+Filters an array (or map values) by the expression given. Equivalent to doing `map(select(exp))`.
+

pkg/yqlib/doc/operators/headers/modulo.md

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+# Modulo
+
+Arithmetic modulo operator, returns the remainder from dividing two numbers.