Some chart attribute typos

There are a few typos in the descriptions of chart attributes:

19.15.1 chart:class (some formatting issues)

chart:area:
Proposal: Start new paragraph for 'The area in the xy-pane'...

chart:bar:
Proposal: No new paragraph for 'Where chart:three-dimensional="true"'...

chart:gannt:
Proposal: add missing word: 'shall used' -> 'shall be used'

chart:line:
Proposal: Start new paragraph for 'The attribute chart:interpolation'...

chart:scatter:
Proposal: Start new paragraph for 'The attribute chart:interpolation'...

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19.595.4 <chart:domain> - scatter:
Proposal: Use plural: 'specifies the x coordinate value' -> 'specifies the x coordinate values'

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20.4 chart:auto-size:

Proposal: Use correct attribute names:
'true: svg:x and svg:y' -> 'true: svg:width and svg:height'

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20.11 chart:deep:
Proposal: Remove wrong ')' at the end of the first sentence.

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20.14 chart:error-lower-indicator
Proposal: Reorder words correctly: false: 'not are' -> 'are not'

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20.18 chart:error-upper-indicator
Proposal 1: Use correct attribute name:
'The defined values for the chart:error-lower-indicator attribute are'
->
'The defined values for the chart:error-upper-indicator attribute are'

Proposal2: Reorder words correctly: false: 'not are' -> 'are not'

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20.21 chart:group-bars-per-axis
Proposal: Use correct attribute name:
'chart:error-lower-indicator' -> 'chart:group-bars-per-axis'

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20.28 chart:label-arrangement
Proposal: At the end of the first sentence replace '>' with '.'

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20.29 chart:label-position
Proposal: Use correct attribute name: chart:axis-label-position > chart:label-position (Remove 'axis')