Double backticks on hll, fix type on frequent items

Author: jmalkin

docs/source/frequent_items.rst

@@ -1,7 +1,7 @@
 Frequent Items
 --------------
 
-.. currentmodule:: dataskethches
+.. currentmodule:: datasketches
 
 This sketch is useful for tracking approximate frequencies of items of type `<T>` with optional associated counts `(<T> item, int count)` 
 that are members of a multiset of such items. 

docs/source/hyper_log_log.rst

@@ -7,10 +7,10 @@ If the ONLY use case for sketching is counting uniques and merging, the HLL sket
 This implementation offers three different types of HLL sketch, each with different trade-offs with accuracy, space and performance. 
 These types are specified with the target_hll_type parameter.
 
-In terms of accuracy, all three types, for the same lg_config_k, have the same error distribution as a function of `n`, the number of unique values fed to the sketch.
-The configuration parameter `lg_config_k` is the log-base-2 of `k`, where `k`` is the number of buckets or slots for the sketch.
+In terms of accuracy, all three types, for the same lg_config_k, have the same error distribution as a function of ``n``, the number of unique values fed to the sketch.
+The configuration parameter ``lg_config_k`` is the log-base-2 of ``k``, where ``k`` is the number of buckets or slots for the sketch.
 
-During warmup, when the sketch has only received a small number of unique items (up to about 10% of `k`), this implementation leverages a new class of estimator algorithms with significantly better accuracy.
+During warmup, when the sketch has only received a small number of unique items (up to about 10% of ``k``), this implementation leverages a new class of estimator algorithms with significantly better accuracy.
 
 
 .. autoclass:: _datasketches.tgt_hll_type