legacy_attr => legacy_attrs. (Python-Markdown#870)

Fixes Python-Markdown#868.

docs/change_log/release-3.0.md

@@ -18,7 +18,7 @@ ignored. Previously the keyword was `True` by default and enabled an
 undocumented way to define attributes on document elements. The feature has been
 removed from version 3.0. As most users did not use the undocumented feature, it
 should not affect most users. For the few who did use the feature, it can be
-enabled by using the [Legacy Attributes](../extensions/legacy_attr.md)
+enabled by using the [Legacy Attributes](../extensions/legacy_attrs.md)
 extension.
 
 ### `smart_emphasis` keyword and `smart_strong` extension deprecated

docs/extensions/index.md

@@ -47,7 +47,7 @@ Extension                          | Entry Point    | Dot Notation
     [Tables]             | `tables`       | `markdown.extensions.tables`
 [Admonition]                       | `admonition`   | `markdown.extensions.admonition`
 [CodeHilite]                       | `codehilite`   | `markdown.extensions.codehilite`
-[Legacy Attributes]                | `legacy_attr`  | `markdown.extensions.legacy_attr`
+[Legacy Attributes]                | `legacy_attrs`  | `markdown.extensions.legacy_attrs`
 [Legacy Emphasis]                  | `legacy_em`    | `markdown.extensions.legacy_em`
 [Meta-Data]                        | `meta`         | `markdown.extensions.meta`
 [New Line to Break]                | `nl2br`        | `markdown.extensions.nl2br`
@@ -65,7 +65,7 @@ Extension                          | Entry Point    | Dot Notation
 [Tables]: tables.md
 [Admonition]: admonition.md
 [CodeHilite]: code_hilite.md
-[Legacy Attributes]: legacy_attr.md
+[Legacy Attributes]: legacy_attrs.md
 [Legacy Emphasis]: legacy_em.md
 [Meta-Data]: meta_data.md
 [New Line to Break]: nl2br.md

docs/extensions/legacy_attr.md → docs/extensions/legacy_attrs.md

@@ -54,13 +54,13 @@ You can also define attributes in images:
 
 ## Usage
 
-See [Extensions](index.md) for general extension usage. Use `legacy_attr` as the
+See [Extensions](index.md) for general extension usage. Use `legacy_attrs` as the
 name of the extension.
 
 This extension does not accept any special configuration options.
 
 A trivial example:
 
 ```python
-markdown.markdown(some_text, extensions=['legacy_attr'])
+markdown.markdown(some_text, extensions=['legacy_attrs'])
 ```

mkdocs.yml

@@ -27,7 +27,7 @@ nav:
       - Extra: extensions/extra.md
       - Fenced Code Blocks: extensions/fenced_code_blocks.md
       - Footnotes: extensions/footnotes.md
-      - Legacy Attributes: extensions/legacy_attr.md
+      - Legacy Attributes: extensions/legacy_attrs.md
       - Legacy Emphasis: extensions/legacy_em.md
       - Meta-Data: extensions/meta_data.md
       - New Line to Break: extensions/nl2br.md