// Please enter a detailed description of the issue // Description of the issue:

GitHub style:

When you create a list of bullet items, one line per bullet, Marked correctly renders this as a bulleted list without a paragraph sized blank line between items.

When you create a list of bullet items with a blank line between each bulleted line (like paragraphs), Marked no longer renders each bullet as a paragraph (with extra space between each one), even though Github itself does.

// Please enter a list of steps required to reproduce the issue // Steps to reproduce:

Using:
- GitHub style - Discount (GFM) markdown processor

1. Use the GitHub style
   
2. Use the Discount (GFM) markdown processor
   
3. Create a document with bulleted lists
   
4. Put a blank line between them.
   
5. Note in the Marked render there is NOT a blank line between bulleted items. (There used to be.)

See Github render (and what Marked used to look like):

https://gist.github.com/zentrope/e45dcdedbfb73b6d1fa663dee82290ab

The above doc is also attached.

// If applicable please attach a sample document that causes the issue for you.

// Configuration (do not edit) Marked 2 947 (Direct)

macOS Version: 10.13.5

additionalMathJaxConfig:
allowPageBreakInCode: TRUE
bookTxtIsLeanpub: TRUE
summaryMdIsGitBook: TRUE
codeIsPoetry: TRUE
codeCanWrap: TRUE
collapsibleHeadlines: TRUE
convertGithubCheckboxes: TRUE
convertYAMLToMMD: TRUE
defaultMathJaxConfig: TeX-AMS-MML_HTMLorMML
defaultPreviewStyle: 3
defaultProcessor: Discount (GFM)
enableMiniMap: TRUE
excludeBlockQuotesFromCounts: TRUE
excludeFootnotesFromCounts: TRUE
excludeVerbatimFromCounts: TRUE
excludeCaptionsFromCounts: TRUE
folderPreviewExtensionsArray: md, markdown, txt, mdown, html, opml
githubNewlines: TRUE
h1IsPageBreak: TRUE
h2IsPageBreak: TRUE
hrIsPageBreak: TRUE
includeMathJax: TRUE
limitTextWidth: TRUE
minimalJavaScript: TRUE
outlineModeExtensions:
permissionGranted: TRUE
printHeaderBottomLeft:
printHeaderBottomRight:
printHeaderFirstPage: TRUE
printFooterFirstPage: TRUE
printHeaderTopLeft:
printHeaderTopRight:
processHTMLFiles: TRUE
removeMetadataForPreview: TRUE
removeYAMLHeaders: TRUE
scrollToEdit: TRUE
shouldDetectCritic: TRUE
shouldHighlightMarkupErrors: TRUE
shouldLoadCritic: TRUE
syntaxHighlight: TRUE