A piece of inline content: text with optional marks, a mention of a resource, or a line break.
Runs are normalized on write, so empty runs are dropped and adjacent runs with identical marks merge.
Example
constcontent: Run[] = runs(['Ruled by ', bold('Princess Bubblegum')])
A piece of inline content: text with optional marks, a mention of a resource, or a line break. Runs are normalized on write, so empty runs are dropped and adjacent runs with identical marks merge.