whitespace: fix double "on" in result text

Resolves: #633
Signed-off-by: Arthur Zamarin <arthurzam@gentoo.org>

Author: arthurzam

src/pkgcheck/checks/whitespace.py

@@ -20,23 +20,23 @@ def __init__(self, leadtrail, **kwargs):
 
     @property
     def desc(self):
-        return f"ebuild has {self.leadtrail} whitespace on {self.lines_str}"
+        return f"ebuild has {self.leadtrail} whitespace {self.lines_str}"
 
 
 class WrongIndentFound(_Whitespace):
     """Incorrect indentation whitespace found."""
 
     @property
     def desc(self):
-        return f"ebuild has whitespace in indentation on {self.lines_str}"
+        return f"ebuild has whitespace in indentation {self.lines_str}"
 
 
 class DoubleEmptyLine(_Whitespace):
     """Unneeded blank lines found."""
 
     @property
     def desc(self):
-        return f"ebuild has unneeded empty line on {self.lines_str}"
+        return f"ebuild has unneeded empty line {self.lines_str}"
 
 
 class TrailingEmptyLine(results.VersionResult, results.Style):