XML warnings

inclusion: Warn about inclusions in element type declarations.
exclusion: Warn about exclusions in element type declarations.
rcdata-content: Warn about RCDATA declared content in element type declarations.
cdata-content: Warn about CDATA declared content in element type declarations.
ps-comment: Warn about comments in parameter separators.
attlist-group-decl: Warn about name groups in attribute declarations.
element-group-decl: Warn about name groups in element type declarations.
pi-entity: Warn about PI entities.
internal-sdata-entity: Warn about internal SDATA entities.
internal-cdata-entity: Warn about internal CDATA entities.
external-sdata-entity: Warn about external SDATA entities.
external-cdata-entity: Warn about external CDATA entities.
bracket-entity: Warn about bracketed text entities.
data-atts: Warn about attribute definition list declarations for notations.
missing-system-id: Warn about external identifiers without system identifiers.
conref: Warn about content reference attributes.
current: Warn about current attr