Adjust TrimmedString regex

This should now match up with the strings that `String.trim` produces.
I had to change `.*` to `(?s:.*)` because the line separator character
isn't removed by `trim` yet doesn't match `.*` without the `s` flag, so
a string like `"\u2028"` can be the result of `trim` but didn't
previously match the regular expression.

Scalastyle and scalafmt had some competing opinions on how I should
format this long regex Witness expression.

modules/core/shared/src/main/scala/eu/timepit/refined/types/string.scala

@@ -43,8 +43,16 @@ object string {
 
   object NonEmptyString extends RefinedTypeOps[NonEmptyString, String]
 
-  /** A `String` that contains no leading or trailing whitespace. */
-  type TrimmedString = String Refined MatchesRegex[W.`"""^(?!\\s).*(?<!\\s)"""`.T]
+  // scalastyle:off no.whitespace.after.left.bracket
+  /**
+   * A `String` that contains no leading or trailing whitespace.
+   *
+   * Note that a line separator (`\u2028') is not considered whitespace for the
+   * purposes of trimming.
+   */
+  type TrimmedString = String Refined MatchesRegex[
+    W.`"""^(?![\\x{0000}-\\x{0020}])(?s:.*)(?<![\\x{0000}-\\x{0020}])"""`.T]
+  // scalastyle:on no.whitespace.after.left.bracket
 
   object TrimmedString extends RefinedTypeOps[TrimmedString, String] {
 
@@ -57,15 +65,6 @@ object string {
      *
      * scala> TrimmedString.trim(" \n a b c ")
      * res0: TrimmedString = a b c
-     *
-     * Note that there are some strings can inhabit `TrimmedString` but will
-     * still be trimmed when passed into this method:
-     *
-     * scala> TrimmedString("\u0000a")
-     * res1: TrimmedString = \u000a
-     *
-     * scala> TrimmedString.trim("\u0000a")
-     * res2: TrimmedString = a
      * }}}
      */
     def trim(s: String): TrimmedString = Refined.unsafeApply(s.trim)

modules/core/shared/src/test/scala/eu/timepit/refined/types/StringTypesSpec.scala

@@ -35,6 +35,10 @@ class StringTypesSpec extends Properties("StringTypes") {
     (truncated.value ?= str.take(FString3.maxLength))
   }
 
+  property("""TrimmedString.from(str)""") = forAll { (str: String) =>
+    TrimmedString.from(str).isRight ?= (TrimmedString.trim(str).value == str)
+  }
+
   property("""TrimmedString.trim(str)""") = forAll { (str: String) =>
     val trimmed = TrimmedString.trim(str)
     TrimmedString.from(trimmed.value) ?= Right(trimmed)