fix docx parse error(\n in alt) (#1163)

Author: BetterAndBetterII

packages/markitdown/src/markitdown/converters/_markdownify.py

@@ -95,6 +95,8 @@ def convert_img(
         src = el.attrs.get("src", None) or el.attrs.get("data-src", None) or ""
         title = el.attrs.get("title", None) or ""
         title_part = ' "%s"' % title.replace('"', r"\"") if title else ""
+        # Remove all line breaks from alt
+        alt = alt.replace("\n", " ")
         if (
             convert_as_inline
             and el.parent.name not in self.options["keep_inline_images_in"]