update(CSS): web/css/css_values_and_units/value_definition_syntax (#3876)

Co-authored-by: Vitalii Perehonchuk <vitalii_perehonchuk@epam.com>

Author: undead404

…web/css/value_definition_syntax/index.md …d_units/value_definition_syntax/index.mdfiles/uk/web/css/value_definition_syntax/index.md renamed to files/uk/web/css/css_values_and_units/value_definition_syntax/index.md files/uk/web/css/value_definition_syntax/index.md renamed to files/uk/web/css/css_values_and_units/value_definition_syntax/index.md

@@ -1,6 +1,6 @@
 ---
 title: Синтаксис визначення значення
-slug: Web/CSS/Value_definition_syntax
+slug: Web/CSS/CSS_Values_and_Units/Value_definition_syntax
 page-type: guide
 spec-urls: https://drafts.csswg.org/css-values/#value-defs
 ---