These should all get escaped:

Backslash: \\

Backtick: \`

Asterisk: \*

Underscore: \_

Left brace: \{

Right brace: \}

Left bracket: \[

Right bracket: \]

Left paren: \(

Right paren: \)

Greater-than: \>

Hash: \#

Period: \.

Bang: \!

Plus: \+

Minus: \-

Tilde: \~

Dollar: \$

These should not, because they occur within a code block:

	Backslash: \\

	Backtick: \`

	Asterisk: \*

	Underscore: \_

	Left brace: \{

	Right brace: \}

	Left bracket: \[

	Right bracket: \]

	Left paren: \(

	Right paren: \)

	Greater-than: \>

	Hash: \#

	Period: \.

	Bang: \!

	Plus: \+

	Minus: \-

	Tilde: \~

	Dollar: \$


Nor should these, which occur in code spans:

Backslash: `\\`

Backtick: `` \` ``

Asterisk: `\*`

Underscore: `\_`

Left brace: `\{`

Right brace: `\}`

Left bracket: `\[`

Right bracket: `\]`

Left paren: `\(`

Right paren: `\)`

Greater-than: `\>`

Hash: `\#`

Period: `\.`

Bang: `\!`

Plus: `\+`

Minus: `\-`

Tilde: `\~`

Dollar: `\$`


These should get escaped, even though they're matching pairs for
other Markdown constructs:

\*asterisks\*

\_underscores\_

\`backticks\`

This is a code span with a literal backslash-backtick sequence: `` \` ``

This is a tag with unescaped backticks <span attr='`ticks`'>bar.

This is a tag with backslashes bar.
