Cleanup some blank problems in all buffer or at region.
It usually applies to the whole buffer, but in transient mark
mode when the mark is active, it applies to the region. It also
applies to the region when it is not in transient mark mode, the
mark is active and C-u was pressed just before
calling `whitespace-cleanup' interactively.
See also `whitespace-cleanup-region'.
The problems cleaned up are:
1. empty lines at beginning of buffer.
2. empty lines at end of buffer.
If `whitespace-style' includes the value `empty', remove all
empty lines at beginning and/or end of buffer.
3. 8 or more SPACEs at beginning of line.
If `whitespace-style' includes the value `indentation':
replace 8 or more SPACEs at beginning of line by TABs, if
`indent-tabs-mode' is non-nil; otherwise, replace TABs by
SPACEs.
If `whitespace-style' includes the value `indentation::tab',
replace 8 or more SPACEs at beginning of line by TABs.
If `whitespace-style' includes the value `indentation::space',
replace TABs by SPACEs.
4. SPACEs before TAB.
If `whitespace-style' includes the value `space-before-tab':
replace SPACEs by TABs, if `indent-tabs-mode' is non-nil;
otherwise, replace TABs by SPACEs.
If `whitespace-style' includes the value
`space-before-tab::tab', replace SPACEs by TABs.
If `whitespace-style' includes the value
`space-before-tab::space', replace TABs by SPACEs.
5. SPACEs or TABs at end of line.
If `whitespace-style' includes the value `trailing', remove
all SPACEs or TABs at end of line.
6. 8 or more SPACEs after TAB.
If `whitespace-style' includes the value `space-after-tab':
replace SPACEs by TABs, if `indent-tabs-mode' is non-nil;
otherwise, replace TABs by SPACEs.
If `whitespace-style' includes the value
`space-after-tab::tab', replace SPACEs by TABs.
If `whitespace-style' includes the value
`space-after-tab::space', replace TABs by SPACEs.
See `whitespace-style', `indent-tabs-mode' and `tab-width' for
documentation.
(fn)