Fix error message for long lines with URLs.

Fix typo.
Remove line break in string's code formatting, to enable
searching the code for particular string.

Signed-off-by: Mateusz Starzyk <mateusz.starzyk@mobica.com>
diff --git a/scripts/assemble_changelog.py b/scripts/assemble_changelog.py
index a7477aa..56d6c37 100755
--- a/scripts/assemble_changelog.py
+++ b/scripts/assemble_changelog.py
@@ -225,9 +225,8 @@
             for line_number, line in enumerate(body_split, 1):
                 if not self._only_url_re.match(line) and \
                    len(line) > MAX_LINE_LENGTH:
-                    long_url_msg = '. URL exceeding length limit must be ' \
-                        'alone in it\'s line.' if self._has_url_re.match(line)  \
-                        else ""
+                    long_url_msg = '. URL exceeding length limit must be alone in its line.' \
+                        if self._has_url_re.match(line) else ""
                     raise InputFormatError(filename,
                                            category.body_line + line_number,
                                            'Line is longer than allowed: '