termui: integrate go-term-markdown

Gopkg.lock

Gopkg.toml

doc/man/git-bug-bridge-configure.1

doc/md/git-bug_bridge_configure.md

misc/bash_completion/git-bug

misc/powershell_completion/git-bug

misc/zsh_completion/git-bug

termui/show_bug.go

vendor/github.com/MichaelMure/go-term-markdown/.gitignore

vendor/github.com/MichaelMure/go-term-markdown/.travis.yml

vendor/github.com/MichaelMure/go-term-markdown/LICENSE

vendor/github.com/MichaelMure/go-term-markdown/Readme.md

vendor/github.com/MichaelMure/go-term-markdown/colors.go

vendor/github.com/MichaelMure/go-term-markdown/go.mod

vendor/github.com/MichaelMure/go-term-markdown/go.sum

vendor/github.com/MichaelMure/go-term-markdown/html.go

vendor/github.com/MichaelMure/go-term-markdown/markdown.go

vendor/github.com/MichaelMure/go-term-markdown/numbering.go

vendor/github.com/MichaelMure/go-term-markdown/options.go

vendor/github.com/MichaelMure/go-term-markdown/renderer.go