fix: Strip backslash before # in generated docstrings (#677)

Author: Alan4506

codegen/core/src/main/java/software/amazon/smithy/python/codegen/writer/MarkdownConverter.java

@@ -170,8 +170,7 @@ private static String postProcessPandocOutput(String output) {
 
         // Remove unnecessary backslash escapes that pandoc adds for markdown
         // These characters don't need escaping in Python docstrings
-        // Handles: [ ] ' { } ( ) < > ` @ _ * | ! ~ $
-        output = output.replaceAll("\\\\([\\[\\]'{}()<>`@_*|!~$])", "$1");
+        output = output.replaceAll("\\\\([\\[\\]'{}()<>`@_*|!~$#])", "$1");
 
         // Replace <note> and <important> tags with admonitions for mkdocstrings
         output = replaceAdmonitionTags(output, "note", "Note");