Fix chapter recognition regex and detail number (#1213)

* Update basic filter for sources that include space between numbers

Wasnts matching on  vol. 1 ch. 10 previously so mangadex last chapter was showing volume number.

* Don't show last chapter number when there are 0 chapters or chapters with no numbers.

This prevents one shots from showing with -1 as last chapter and instead just leaves it blank

* added else to be Unknown instead of blank

* removed empty line
added test case

* switched to null safe ?.

* Revert "switched to null safe ?."

This reverts commit 97a9300d1bedc8e01efb439c180eced8eaa1da5b.
undo

* switched to null safe ?.

app/src/main/java/eu/kanade/tachiyomi/util/ChapterRecognition.kt

@@ -11,7 +11,7 @@ object ChapterRecognition {
      * All cases with Ch.xx
      * Mokushiroku Alice Vol.1 Ch. 4: Misrepresentation -R> 4
      */
-    private val basic = Regex("""(?<=ch\.)([0-9]+)(\.[0-9]+)?(\.?[a-z]+)?""")
+    private val basic = Regex("""(?<=ch\.) *([0-9]+)(\.[0-9]+)?(\.?[a-z]+)?""")
 
     /**
      * Regex used when only one number occurrence