Document dfr/reduce-+ & dfr/reduce-* (#104)

* add docsctrings for the methods dfr/reduce-+ & dfr/reduce-*

* finish documenting all the functions named like reduce-

src/tech/v3/datatype/functional.clj

@@ -715,21 +715,61 @@ tech.v3.datatype.functional> (meta regressor)
 
 
 (defn reduce-*
+  "Invokes a reduce operation with the operand * to multiply items together.
+
+  Examples:
+
+  ```clojure
+  user> (dfn/reduce-* [1 2 3 4])
+  24
+  user> (dfn/reduce-* [-1 1.1 4])
+  -4.4
+  ```"
   ([x]
   (tech.v3.datatype.functional-api/reduce-* x)))
 
 
 (defn reduce-+
+  "Invokes a reduce operation with the operand + to add items together.
+
+  Examples:
+
+  ```clojure
+  user> (dfn/reduce-+ [1 2 3 4])
+  10
+  user> (dfn/reduce-+ [-1 1.1 4])
+  4.1
+  ```"
   ([x]
   (tech.v3.datatype.functional-api/reduce-+ x)))
 
 
 (defn reduce-max
+  "Invokes a reduce operation with the operand max find the maximum item of a list.
+
+  Examples:
+
+  ```clojure
+  user> (dfn/reduce-max [1 2 3 4])
+  4
+  user> (dfn/reduce-max [10 -10 20 100 -1])
+  100
+  ```"
   ([x]
   (tech.v3.datatype.functional-api/reduce-max x)))
 
 
 (defn reduce-min
+  "Invokes a reduce operation with the operand min find the minimum item of a list.
+
+  Examples:
+
+  ```clojure
+  user> (dfn/reduce-min [1 2 3 4])
+  1
+  user> (dfn/reduce-min [10 -10 20 100 -1])
+  -10
+  ```"
   ([x]
   (tech.v3.datatype.functional-api/reduce-min x)))
 

src/tech/v3/datatype/functional_api.clj

@@ -132,25 +132,65 @@
 
 ;;Implement only reductions that we know we will use.
 (defn reduce-+
+  "Invokes a reduce operation with the operand + to add items together.
+
+  Examples:
+
+  ```clojure
+  user> (dfn/reduce-+ [1 2 3 4])
+  10
+  user> (dfn/reduce-+ [-1 1.1 4])
+  4.1
+  ```"
   [x]
   ;;There is a fast path specifically for summations
   (dtype-reductions/commutative-binary-reduce
    (:tech.numerics/+ binary-op/builtin-ops) x))
 
 
 (defn reduce-*
+  "Invokes a reduce operation with the operand * to multiply items together.
+
+  Examples:
+
+  ```clojure
+  user> (dfn/reduce-* [1 2 3 4])
+  24
+  user> (dfn/reduce-* [-1 1.1 4])
+  -4.4
+  ```"
   [x]
   (dtype-reductions/commutative-binary-reduce
    (:tech.numerics/* binary-op/builtin-ops) x))
 
 
 (defn reduce-max
+  "Invokes a reduce operation with the operand max find the maximum item of a list.
+
+  Examples:
+
+  ```clojure
+  user> (dfn/reduce-max [1 2 3 4])
+  4
+  user> (dfn/reduce-max [10 -10 20 100 -1])
+  100
+  ```"
   [x]
   (dtype-reductions/commutative-binary-reduce
    (:tech.numerics/max binary-op/builtin-ops) x))
 
 
 (defn reduce-min
+  "Invokes a reduce operation with the operand min find the minimum item of a list.
+
+  Examples:
+
+  ```clojure
+  user> (dfn/reduce-min [1 2 3 4])
+  1
+  user> (dfn/reduce-min [10 -10 20 100 -1])
+  -10
+  ```"
   [x]
   (dtype-reductions/commutative-binary-reduce
    (:tech.numerics/min binary-op/builtin-ops) x))