On Jira (7.2.1), how can I view all issues that were, at some point, assigned to me

You can enable the Epic Link field to be shown (in your projects screen scheme). Then every card will have a field UI for selecting which Epic it is associated with.

This is the modern / current convention.

The Atlassian JIRA {code} macro is covered in section Advanced Formatting within the Text Formatting Notation Help:

Makes a preformatted block of code with syntax highlighting. All the optional parameters of {panel} macro are valid for {code} too. The default language is Java but you can specify others too, including ActionScript, Ada, AppleScript, bash, C, C#, C++, CSS, Erlang, Go, Groovy, Haskell, HTML, JavaScript, JSON, Lua, Nyan, Objc, Perl, PHP, Python, R, Ruby, Scala, SQL, Swift, VisualBasic, XML and YAML.

Example:

{code:title=Bar.java|borderStyle=solid}
// Some comments here
public String getFoo()
{
    return foo;
}
{code}

{code:xml}
    <test>
      <another tag="attribute"/>
    </test>
{code}