Format Markdown text for file attachment and screenshot comments.
Format Markdown text for file attachment and screenshot comments.

Only diff comments were formatting Markdown text. Other comment types
ignored it completely and assumed it was plain text. Now it works for
all comment types.

1tush/reviewboard,bkochendorfer/reviewboard,davidt/reviewboard,beol/reviewboard,chipx86/reviewboard,davidt/reviewboard,KnowNo/reviewboard,1tush/reviewboard,chipx86/reviewboard,1tush/reviewboard,1tush/reviewboard,sgallagher/reviewboard,sgallagher/reviewboard,brennie/reviewboard,bkochendorfer/reviewboard,reviewboard/reviewboard,bkochendorfer/reviewboard,KnowNo/reviewboard,brennie/reviewboard,custode/reviewboard,custode/reviewboard,1tush/reviewboard,bkochendorfer/reviewboard,chipx86/reviewboard,chipx86/reviewboard,1tush/reviewboard,davidt/reviewboard,beol/reviewboard,1tush/reviewboard,reviewboard/reviewboard,custode/reviewboard,reviewboard/reviewboard,brennie/reviewboard,beol/reviewboard,1tush/reviewboard,1tush/reviewboard,sgallagher/reviewboard,reviewboard/reviewboard,brennie/reviewboard,KnowNo/reviewboard,custode/reviewboard,beol/reviewboard,sgallagher/reviewboard,KnowNo/reviewboard,davidt/reviewboard