Normalize shell and patch tool cards

app/androidApp/src/main/kotlin/com/example/aiapp/Languages.kt

@@ -16,6 +16,7 @@ enum class Language {
     CPP,
     CSHARP,
     DART,
+    DIFF,
     FISH,
     GO,
     JAVA,
@@ -100,7 +101,7 @@ fun spansOf(code: String, language: Language): List<Span> = SCANNERS.getValue(la
 // Lazy for the same reason [RULES] is, since it reads it.
 private val SCANNERS: Map<Language, (String) -> List<Span>> by lazy {
     RULES.mapValues { (_, rules) -> { code: String -> scan(code, rules) } } +
-        mapOf(Language.MARKDOWN to ::scanMarkdown)
+        mapOf(Language.DIFF to ::scanDiff, Language.MARKDOWN to ::scanMarkdown)
 }
 
 private val C_STYLE = BlockComment("/*", "*/", nests = false)