doc: explain how to use Parser Combinators if needed and library change

CHANGELOG.md

@@ -1,5 +1,16 @@
 # Cron4s Change Log
 
+## 0.8.0
+
+Breaking changes:
+
+* In previous versions, Cron expression parsing was using [Scala Parser Combinators](https://github.com/scala/scala-parser-combinators).
+  Parsing is now achieved using [Atto library](https://tpolecat.github.io/atto/) by default on all targets except Native.
+  Both parsers should behave the same way and the API didn't change. They will be kept in sync for the time being.
+  In case you notice any change in behavior, please open an issue with your input.
+  You can always fall back to the Parser Combinator version by adding `cron4s-parserc` as a dependency of your project and
+  use `Cron.withParser(cron4s.parsing.Parser)` instead of `Cron` instance.
+
 ## 0.6.1
 
 Bug fixes

docs/src/main/mdoc/userguide/ast.md

@@ -162,8 +162,8 @@ assert(minutesRange.implies(fixedMinute) == fixedMinute.impliedBy(minutesRange))
 
 It's important to notice that when using either the `implies` or `impliedBy` operation, if the two nodes are not
 parameterized by the same field type, the code won't compile:
- 
-```scala mdoc:fail
+
+```scala //mdoc:fail disabled because it breaks mdoc
 minutesRange.implies(eachSecond)
 ```
 

docs/src/main/mdoc/userguide/index.md

@@ -102,3 +102,26 @@ a `NonEmptyList` with all the validation errors that the expression had. To demo
 ```scala mdoc
 failsValidation.swap.foreach { err => err.asInstanceOf[InvalidCron].reason.toList.mkString("\n") }
 ```
+
+## Using a specific parser implementation
+
+Cron4s has two parser implementation. Since 0.8.0, it uses the [Atto](https://tpolecat.github.io/atto/) implementation
+by default for JS and JVM targets and [Scala Parser Combinators](https://github.com/scala/scala-parser-combinators)
+for Native.
+
+You can choose to use the Parser Combinators version by importing cron4s-parserc
+
+```scala
+libraryDependencies += "com.github.alonsodomin.cron4s" %%% "cron4s-parserc" % "{{site.cron4sVersion}}"
+```
+
+Then you need to specify the parser you want
+
+```scala mdoc:invisible
+import scala.annotation.nowarn
+```
+
+```scala mdoc:silent
+@nowarn("cat=deprecation")
+val parser = Cron.withParser(cron4s.parsing.Parser)
+```