Describe the bug
Extracting messages that occurs in several places in the code results in an entry containing all references on a dedicated line:

#: js/chart/HistoryChart.tsx:74
#: js/chart/LiveChart.tsx:77
msgid "Loading chart…"
msgstr ""

Expected behavior
Extracting messages that occurs in several places in the code should result in an entry containing all reference

ECMA-402 includes RelativeTimeFormat, a formatter that supports relative durations (such as "1 hour ago").

Under the hood, RelativeTimeFormat relies on fairly straightforward CLDR data described in [UTS 35](https://unicode.org/reports/tr35/tr35-dates.html#Calendar_Field

Are there any cheat sheets of stringi available? Like this one of stringr: http://edrub.in/CheatSheets/cheatSheetStringr.pdf

It would be more efficient to have a cheat sheet since R base, stringr, and stringi have different but similar types of syntax, which could be confusing some times.

Right now we only support either a custom message syntax validator or the ICU Message Syntax. We can start to add builtin support for other syntaxes