fix typo.

app.py

@@ -98,7 +98,7 @@ with st.sidebar:
         'How would you like to be your Headlines?',
         ('**Emphasis**', '# Header', 'No headlines'))
 
-        if in_headline_type =! 'No headlines'
+        if in_headline_type!='No headlines':
             in_headlines = st.text_area("Headlines: ", placeholder="Enter each headline in one line. e.g.,\nWelcome\nConcise Description\nAdditional Info", on_change=None, height=200)
         else:
             in_headline_type = '<|EMPTY|>'