fix(deps): update dependency markdown to v7

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
markdown (source)	dependencies	major	^4.0.1 → 7.3.0

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Release Notes

dart-lang/tools (markdown)

v7.3.0

• Move to dart-lang/tools monorepo.
• Fix an issue with checkbox list items separated with blank lines (#​602).
• Require package web: '>=0.4.2 <2.0.0'.
• Fix several RangeError hazards in links (#​623).
• Export LinkReferenceDefinitionSyntax publicly (#​626).

v7.2.2

• Fix a crash parsing alert block syntax (#​584).
• Have alert block syntax support multiple paragraphs (#​577).
• Require Dart ^3.2.0.

v7.2.1

• Address a termination issue with GitHub alert syntax parsing.

v7.2.0

• Require Dart ^3.1.0.
• Update all CommonMark specification links to 0.30.
• Fix beginning of line detection in AutolinkExtensionSyntax.
• Add a new syntax AlertBlockSyntax to parse GitHub Alerts.

v7.1.1

• Fix delimiter row matching pattern for tables.
• Tables are now able to interrupt other blocks.
• Fix an obscure issue with HtmlBlockSyntax.

v7.1.0

Compare Source

• Support for footnotes.
• Fixed bug causing infinite loop for links inside tables.

v7.0.2

Compare Source

• Require Dart 2.19
• Fix an issue in HeaderWithIdSyntax, do not generate heading IDs for headings
  with no content.

v7.0.1

Compare Source

• Remove RegExp lookarounds from autolink extension patterns. (Fixes issues when
  running on Safari.)

v7.0.0

Compare Source

• Breaking change: close() of DelimiterSyntax and LinkSyntax
  returns multiple nodes instead of single one.
• Breaking change: Remove deprecated APIs, including TagSyntax,
  indicatorForCheckedCheckBox, and indicatorForUncheckedCheckBox.
• Breaking change: Removed BlockHtmlSyntax, BlockTagBlockHtmlSyntax,
  LongBlockHtmlSyntax, and OtherTagBlockHtmlSyntax.
• Breaking change: Change the line properties of type String to Line.
• Breaking change: Change the lines properties of type List<String> to
  List<Line>.
• Add a new syntax HtmlBlockSyntax to parse HTML blocks.
• Add an enableTagfilter option to HtmlRenderer to eanble GFM tagfilter
  extension.
• Add a new syntax DecodeHtmlSyntax to decode HTML entity and numeric
  character references.
• Add a new syntax SoftLineBreakSyntax to remove the single space before the
  line ending.
• Add a new syntax EscapeHtmlSyntax to encode ("), (<), (>) and (&).
• Add an option caseSensitive to TextSyntax.
• Add a new public method parse(String text) for Document.
• Add a new public method parseLineList(List<Line> text) for Document.
• Add a new type: Line.
• Add a new optional parameter parentSyntax for parseLines() of
  BlockParser, which can be used when parsing nested blocks.
• Add a new optional parameter disabledSetextHeading for parseLines() of
  BlockParser, which is used to disable the SetextHeaderSyntax.
• Add a new public property previousSyntax for BlockParser.

v6.0.1

Compare Source

• Fix a crash in checkbox lists when mixing checkbox items with
  non-checkbox items.

v6.0.0

Compare Source

• Require Dart 2.17
• Add support to GFM extension for GitHub task lists (aka checkboxes). These
  are only active in the gitHubFlavored and gitHubWeb extension sets.
• Add support for #ff0000 color swatches.
• Change emoji list do be derived from the GitHub API. The only two emoji that
  visually change are :cricket: and :beetle:. There are alternate emoji
  :cricket_game: and :lady_beetle: which can be used to access the previous
  emoji. update_github_emoji.dart now pulls all emoji info directly from
  GitHub API and as a result we have now support the entire GitHub emoji set
  (excluding the 19 custom GitHub specific emoji which have no Unicode support).
• Breaking change: The TagSyntax is deprecated.
• Add new syntax DelimiterSyntax.
• Breaking change: StrikethroughSyntax now extends DelimiterSyntax
  instead of TagSyntax.
• Breaking change: LinkSyntax now extends DelimiterSyntax
  instead of TagSyntax.
• Add two new emphasis syntaxes EmphasisSyntax.underscore and
  EmphasisSyntax.asterisk.

v5.0.0

Compare Source

• Breaking change: Change the type of parseInline's parameter from String?
  to String.
• Fix table-rendering bug when table rows have trailing whitespace.
  #​368.
• Do not allow reference link labels to contain left brackets. Thanks
  @​chenzhiguang.
  #​335.
• Treat lines matching a code block syntax as continuations of paragraphs,
  inside blockquotes. Thanks @​chenzhiguang.
  #​358.
• Add a syntax for GitLab-flavored fenced blockquotes. GitLab-flavored Markdown
  will be evaluated into an ExtensionSet, in a future release. Thanks
  @​chenzhiguang.
  #​359.
• Add bool withDefaultInlineSyntaxes and bool withDefaultBlockSyntaxes
  parameters to markdownToHtml and Document to support the case of
  specifying exactly the list of desired syntaxes. Thanks @​chenzhiguang.
  #​393.

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