Adds doctest examples for the hash tutorial (#2821)

* Create dt_hash.py

creating the python hash data type examples that will be used in conjunction with the hashes.md file in docs to show tabbed examples

* Fixes some steps not showing

* Fixes instructions for doctests

* Making linter happy

* Format result as per Igor’s suggestion

* Change all the other outputs to Igor’s suggestion

* make linter happy

---------

Co-authored-by: Elena Kolevska <elena@kolevska.com>

doctests/README.md

@@ -16,8 +16,8 @@ Examples are standalone python scripts, committed to the *doctests* directory. T
 ```requirements.txt``` and ```dev_requirements.txt``` from this repository have been installed, as per below.
 
 ```bash
-pip install requirements.txt
-pip install dev_requirements.txt
+pip install -r requirements.txt
+pip install -r dev_requirements.txt
 ```
 
 Note - the CI process, runs the basic ```black``` and ```isort``` linters against the examples. Assuming 

doctests/dt_hash.py

@@ -0,0 +1,103 @@
+# EXAMPLE: hash_tutorial
+# HIDE_START
+import redis
+
+r = redis.Redis(decode_responses=True)
+# HIDE_END
+# STEP_START set_get_all
+res1 = r.hset(
+    "bike:1",
+    mapping={
+        "model": "Deimos",
+        "brand": "Ergonom",
+        "type": "Enduro bikes",
+        "price": 4972,
+    },
+)
+print(res1)
+# >>> 4
+
+res2 = r.hget("bike:1", "model")
+print(res2)
+# >>> 'Deimos'
+
+res3 = r.hget("bike:1", "price")
+print(res3)
+# >>> '4972'
+
+res4 = r.hgetall("bike:1")
+print(res4)
+# >>> {'model': 'Deimos', 'brand': 'Ergonom', 'type': 'Enduro bikes', 'price': '4972'}
+
+# STEP_END
+
+# REMOVE_START
+assert res1 == 4
+assert res2 == "Deimos"
+assert res3 == "4972"
+assert res4 == {
+    "model": "Deimos",
+    "brand": "Ergonom",
+    "type": "Enduro bikes",
+    "price": "4972",
+}
+# REMOVE_END
+
+# STEP_START hmget
+res5 = r.hmget("bike:1", ["model", "price"])
+print(res5)
+# >>> ['Deimos', '4972']
+# STEP_END
+
+# REMOVE_START
+assert res5 == ["Deimos", "4972"]
+# REMOVE_END
+
+# STEP_START hincrby
+res6 = r.hincrby("bike:1", "price", 100)
+print(res6)
+# >>> 5072
+res7 = r.hincrby("bike:1", "price", -100)
+print(res7)
+# >>> 4972
+# STEP_END
+
+# REMOVE_START
+assert res6 == 5072
+assert res7 == 4972
+# REMOVE_END
+
+
+# STEP_START incrby_get_mget
+res11 = r.hincrby("bike:1:stats", "rides", 1)
+print(res11)
+# >>> 1
+res12 = r.hincrby("bike:1:stats", "rides", 1)
+print(res12)
+# >>> 2
+res13 = r.hincrby("bike:1:stats", "rides", 1)
+print(res13)
+# >>> 3
+res14 = r.hincrby("bike:1:stats", "crashes", 1)
+print(res14)
+# >>> 1
+res15 = r.hincrby("bike:1:stats", "owners", 1)
+print(res15)
+# >>> 1
+res16 = r.hget("bike:1:stats", "rides")
+print(res16)
+# >>> 3
+res17 = r.hmget("bike:1:stats", ["crashes", "owners"])
+print(res17)
+# >>> ['1', '1']
+# STEP_END
+
+# REMOVE_START
+assert res11 == 1
+assert res12 == 2
+assert res13 == 3
+assert res14 == 1
+assert res15 == 1
+assert res16 == "3"
+assert res17 == ["1", "1"]
+# REMOVE_END