Fixes for Issue 310 - Follow Dart file conventions (#311)

Fix Dart file conventions for pub.dev
diff --git a/CHANGELOG.md b/CHANGELOG.md
index dc00725..124c155 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -161,9 +161,9 @@
 ## 0.11.0
 
 * Parse HTML blocks more accurately, according to
-  [CommonMark](http://spec.commonmark.org/0.24/#html-blocks).
+  [CommonMark](https://spec.commonmark.org/0.24/#html-blocks).
 * Support [shortcut reference
-  links](http://spec.commonmark.org/0.24/#reference-link).
+  links](https://spec.commonmark.org/0.24/#reference-link).
 * Don't allow an indented code block to interrupt a paragraph.
 * Change definition of "loose" and "strict" lists (items wrapped in
   paragraph tags vs not) to CommonMark's. The primary difference is that any
@@ -176,7 +176,7 @@
 
 ## 0.10.1
 
-* Parse [hard line breaks](http://spec.commonmark.org/0.24/#hard-line-breaks)
+* Parse [hard line breaks](https://spec.commonmark.org/0.24/#hard-line-breaks)
   properly (#86). Thanks @mehaase!
 * Fix processing of `[ ... ]` syntax when no resolver is specified (#92).
 * There are now 401/613 (65%) passing CommonMark v0.24 specs.
diff --git a/README.md b/README.md
index 6959a1d..e39f55b 100644
--- a/README.md
+++ b/README.md
@@ -157,14 +157,15 @@
 
  3. Update the stats files as described above. Note any changes in the results.
  4. Update any references to the existing spec by search for
-    `http://spec.commonmark.org/0.28` in the repository. (Including this one.)
+    `https://spec.commonmark.org/0.28` in the repository. (Including this one.)
     Verify the updated links are still valid.
  5. Commit changes, including a corresponding note in `CHANGELOG.md`.
 
-[Perl Markdown]: http://daringfireball.net/projects/markdown/
-[CommonMark]: http://commonmark.org/
-[commonMark-raw-html]: http://spec.commonmark.org/0.28/#raw-html
+[Perl Markdown]: https://daringfireball.net/projects/markdown/
+[CommonMark]: https://commonmark.org/
+[commonMark-raw-html]: https://spec.commonmark.org/0.28/#raw-html
 [CommonMark source]: https://github.com/jgm/CommonMark/
-[pandoc-auto_identifiers]: http://pandoc.org/README.html#extension-auto_identifiers
+[GitHub Flavored]: https://github.github.com/gfm/
+[pandoc-auto_identifiers]: https://pandoc.org/README.html#extension-auto_identifiers
 ["Markdown's XSS Vulnerability (and how to mitigate it)"]: https://github.com/showdownjs/showdown/wiki/Markdown%27s-XSS-Vulnerability-(and-how-to-mitigate-it)
 [NodeValidator]: https://api.dart.dev/stable/dart-html/NodeValidator-class.html
diff --git a/pubspec.yaml b/pubspec.yaml
index a23d01a..b1ba48d 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,7 +1,8 @@
 name: markdown
 version: 2.1.8
 
-description: A library for converting markdown to HTML.
+description: A portable Markdown library written in Dart that can parse
+ Markdown into HTML.
 homepage: https://github.com/dart-lang/markdown
 
 executables: