Add markdown support

[viktor02]

Hi, it would be great if sumatrapdf could open markdown files

[GitHubRulesOK]

I know its not what you are after, however since the whole point of MD is to be as a minimum readable as txt then you could add the .txt extension and the links work unlike NotePad or Edge

[GitHubRulesOK]

@kjk it would help if .md was an acceptable extension just the same as .txt Readme.zip

Also as a side issue .txt is tied to ebookui false otherwise it will not normally be accepted, and I know I should not be pushing .vbkm envelope but test out the one enclosed for the MD which exemplifies the reason there was a issue requesting "padding" space after last page in order to scroll to lower entries

[ghost]

Any updates here?

[kjk]

no updates