Fix typos/grammar in docs (#2201)

docs/conf.py

@@ -234,7 +234,7 @@ latex_additional_files = ['flaskstyle.sty', 'logo.pdf']
 # The scheme of the identifier. Typical schemes are ISBN or URL.
 #epub_scheme = ''
 
-# The unique identifier of the text. This can be a ISBN number
+# The unique identifier of the text. This can be an ISBN number
 # or the project homepage.
 #epub_identifier = ''
 

docs/patterns/fileuploads.rst

@@ -58,7 +58,7 @@ the file and redirects the user to the URL for the uploaded file::
                 return redirect(request.url)
             file = request.files['file']
             # if user does not select file, browser also
-            # submit a empty part without filename
+            # submit an empty part without filename
             if file.filename == '':
                 flash('No selected file')
                 return redirect(request.url)

docs/styleguide.rst

@@ -167,7 +167,7 @@ Docstring conventions:
         """
 
 Module header:
-  The module header consists of an utf-8 encoding declaration (if non
+  The module header consists of a utf-8 encoding declaration (if non
   ASCII letters are used, but it is recommended all the time) and a
   standard docstring::
 

docs/upgrading.rst

@@ -49,7 +49,7 @@ Any of the following is functionally equivalent::
     response = send_file(open(fname), attachment_filename=fname)
     response.set_etag(...)
 
-The reason for this is that some file-like objects have a invalid or even
+The reason for this is that some file-like objects have an invalid or even
 misleading ``name`` attribute. Silently swallowing errors in such cases was not
 a satisfying solution.
 
@@ -198,7 +198,7 @@ applications with Flask.  Because we want to make upgrading as easy as
 possible we tried to counter the problems arising from these changes by
 providing a script that can ease the transition.
 
-The script scans your whole application and generates an unified diff with
+The script scans your whole application and generates a unified diff with
 changes it assumes are safe to apply.  However as this is an automated
 tool it won't be able to find all use cases and it might miss some.  We
 internally spread a lot of deprecation warnings all over the place to make