Mismatched concept_type and type Concept attributes

[rossbowen]

Describe the bug

A small one - but the Concept class defines an attribute called concept_type but parse_taxonomy() sets type instead.

Happy to submit a PR but unsure of whether to converge on concept_type or type.

py-xbrl/xbrl/taxonomy.py

Line 477 in 16c555c

self.concept_type: str or None = None

py-xbrl/xbrl/taxonomy.py

Lines 676 to 677 in 16c555c

	concept = Concept(el_id, schema_url, el_name)
	concept.type = element.attrib['type'] if 'type' in element.attrib else False

[rossbowen]

Additionally, concept.type defaults to False but possibly should default to None.