Add shtml extension to known HTML extensions (#56)

Author: cengelbart39

Sources/CodeEditLanguages/CodeLanguage+Definitions.swift

@@ -145,7 +145,7 @@ public extension CodeLanguage {
     static let html: CodeLanguage = .init(
         id: .html,
         tsName: "html",
-        extensions: ["html", "htm"],
+        extensions: ["html", "htm", "shtml"],
         highlights: ["injections"]
     )
 

Tests/CodeEditLanguagesTests/CodeEditLanguagesTests.swift

@@ -274,6 +274,13 @@ final class CodeEditLanguagesTests: XCTestCase {
 
         XCTAssertEqual(language.id, .html)
     }
+    
+    func test_CodeLanguageHTML3() throws {
+        let url = URL(fileURLWithPath: "~/path/to/file.shtml")
+        let language = CodeLanguage.detectLanguageFrom(url: url)
+
+        XCTAssertEqual(language.id, .html)
+    }
 
     func test_FetchQueryHTML() throws {
         var language = CodeLanguage.html