This prevents some needless searching for the start of the paragraph
from a run stored in a cursor. Usually a pointer to the paragraph is
already available when the cursor is set anyway.
Previously a count of the carraige returns and line feeds were stored
for end of paragraph runs, and a paragraph sign was stored as the actual
string. This was causing many special cases where the length of the
run needed to be determined differently if the run was or wasn't an
end of paragraph run.
There wasn't any use for storing the paragraph sign unless some drawing
code gets commented out to allow the end paragraphs to be shown,
therefore I changed the code to store the actual string that gets
retrieved by WM_GETTEXT.
The methods in ITextHost are mostly thin wrappers around functions that
take a handle to a window as their first parameter. This patch just
uses the wrapper functions provided by ITextHost instead of using the
functions that require a handle to a window that the editor might now
have (for windowless richedit controls).
