clarify blocks docs (#2060)

CHANGES.rst

@@ -1001,7 +1001,7 @@ Released 2008-07-17, codename Jinjavitus
     evaluates to ``false``.
 -   Improved error reporting for undefined values by providing a
     position.
--   ``filesizeformat`` filter uses decimal prefixes now per default and
+-   ``filesizeformat`` filter uses decimal prefixes now by default and
     can be set to binary mode with the second parameter.
 -   Fixed bug in finalizer
 

docs/templates.rst

@@ -528,8 +528,8 @@ However, the name after the `endblock` word must match the block name.
 Block Nesting and Scope
 ~~~~~~~~~~~~~~~~~~~~~~~
 
-Blocks can be nested for more complex layouts.  However, per default blocks
-may not access variables from outer scopes::
+Blocks can be nested for more complex layouts. By default, a block may not
+access variables from outside the block (outer scopes)::
 
     {% for item in seq %}
         <li>{% block loop_item %}{{ item }}{% endblock %}</li>

docs/tricks.rst

@@ -21,7 +21,7 @@ for a neat trick.
 Usually child templates extend from one template that adds a basic HTML
 skeleton.  However it's possible to put the `extends` tag into an `if` tag to
 only extend from the layout template if the `standalone` variable evaluates
-to false which it does per default if it's not defined.  Additionally a very
+to false, which it does by default if it's not defined.  Additionally a very
 basic skeleton is added to the file so that if it's indeed rendered with
 `standalone` set to `True` a very basic HTML skeleton is added::
 

src/jinja2/loaders.py

@@ -430,7 +430,7 @@ class DictLoader(BaseLoader):
 
     >>> loader = DictLoader({'index.html': 'source here'})
 
-    Because auto reloading is rarely useful this is disabled per default.
+    Because auto reloading is rarely useful this is disabled by default.
     """
 
     def __init__(self, mapping: t.Mapping[str, str]) -> None: