rename fields folders to elements

src/class-elements/class-evaluation-error/cls-decl.template

src/class-elements/class-evaluation-error/cls-expr.template

src/class-elements/default/cls-decl.template

src/class-elements/default/cls-expr.template

...ments/delete-error/cls-decl-field-delete-covered.template

...delete-error/cls-decl-field-delete-twice-covered.template

...lass-elements/delete-error/cls-decl-field-delete.template

...ents/delete-error/cls-decl-method-delete-covered.template

...elete-error/cls-decl-method-delete-twice-covered.template

...ass-elements/delete-error/cls-decl-method-delete.template

...ments/delete-error/cls-expr-field-delete-covered.template

...delete-error/cls-expr-field-delete-twice-covered.template

...lass-elements/delete-error/cls-expr-field-delete.template

...ents/delete-error/cls-expr-method-delete-covered.template

...elete-error/cls-expr-method-delete-twice-covered.template

...ass-elements/delete-error/cls-expr-method-delete.template

...ents/initializer-error/cls-decl-fields-arrow-fnc.template

...ents/initializer-error/cls-decl-fields-comp-name.template

...ments/initializer-error/cls-decl-fields-equality.template

...s/initializer-error/cls-decl-fields-literal-name.template