Function/Class method naming should use lowercase with underscores

[Andrew-Chen-Wang]

Description: upon inspecting many of the new class methods, they don't follow Python convention. In addition to the PR for black and isort, I think the naming convention of these methods should be lowercase with underscores, for instance, _append_scores instead of _appendScores

[chayim]

@Andrew-Chen-Wang You're right. This comes as a direct result of the initial import of the module code into redis-py, and we should change that.

Reviewing, it appears that all of the associated functions are internal only, meaning this is not a breaking change.

@dvora-h Mind having a look? See below as an example of trying to identify these.

 grep -R -E 'def [_]{0,99}[a-z_]{1,}[A-Z]' redis/
redis/commands/bf/__init__.py:    def appendItems(params, items):
redis/commands/bf/__init__.py:    def appendError(params, error):
redis/commands/bf/__init__.py:    def appendCapacity(params, capacity):
redis/commands/bf/__init__.py:    def appendExpansion(params, expansion):
redis/commands/bf/__init__.py:    def appendNoScale(params, noScale):
redis/commands/bf/__init__.py:    def appendWeights(params, weights):
redis/commands/bf/__init__.py:    def appendNoCreate(params, noCreate):
redis/commands/bf/__init__.py:    def appendItemsAndIncrements(params, items, increments):
redis/commands/bf/__init__.py:    def appendValuesAndWeights(params, items, weights):
redis/commands/bf/__init__.py:    def appendMaxIterations(params, max_iterations):
redis/commands/bf/__init__.py:    def appendBucketSize(params, bucket_size):
redis/commands/search/commands.py:    def _get_AggregateResult(self, raw, query, has_cursor):
redis/commands/search/indexDefinition.py:    def _appendIndexType(self, index_type):
redis/commands/search/indexDefinition.py:    def _appendPrefix(self, prefix):
redis/commands/search/indexDefinition.py:    def _appendFilter(self, filter):
redis/commands/search/indexDefinition.py:    def _appendLanguage(self, language_field, language):
redis/commands/search/indexDefinition.py:    def _appendScore(self, score_field, score):
redis/commands/search/indexDefinition.py:    def _appendPayload(self, payload_field):
redis/commands/json/path.py:    def rootPath():
redis/commands/timeseries/commands.py:    def _appendUncompressed(params, uncompressed):
redis/commands/timeseries/commands.py:    def _appendWithLabels(params, with_labels, select_labels=None):
redis/commands/timeseries/commands.py:    def _appendGroupbyReduce(params, groupby, reduce):
redis/commands/timeseries/commands.py:    def _appendRetention(params, retention):
redis/commands/timeseries/commands.py:    def _appendLabels(params, labels):
redis/commands/timeseries/commands.py:    def _appendCount(params, count):
redis/commands/timeseries/commands.py:    def _appendTimestamp(params, timestamp):
redis/commands/timeseries/commands.py:    def _appendAlign(params, align):
redis/commands/timeseries/commands.py:    def _appendAggregation(params, aggregation_type, bucket_size_msec):
redis/commands/timeseries/commands.py:    def _appendChunkSize(params, chunk_size):
redis/commands/timeseries/commands.py:    def _appendDuplicatePolicy(params, command, duplicate_policy):
redis/commands/timeseries/commands.py:    def _appendFilerByTs(params, ts_list):
redis/commands/timeseries/commands.py:    def _appendFilerByValue(params, min_value, max_value):
redis/commands/helpers.py:def decodeDictKeys(obj):
redis/commands/graph/node.py:    def toString(self):
redis/commands/graph/__init__.py:    def relationshipTypes(self):
redis/commands/graph/__init__.py:    def propertyKeys(self):
redis/commands/graph/edge.py:    def toString(self):