fix: fix lint file mime type detection

Author: zdm

lib/lint/file.js

@@ -353,14 +353,12 @@ export class LintFile {
 
             type ||= customMime.findByFilename( this.#fullPath )?.essence;
 
-            type ||= (
-                await customMime.findByShebang( {
-                    "path": this.#fullPath,
-                    "content": await this.#file.slice( 0, 50 ).text( "latin1" ),
-                } )
-            )?.essence;
-
-            type ||= this.#file.type;
+            if ( !type ) {
+                type =
+                    customMime.findByShebangSync( {
+                        "content": ( await this.#file.slice( 0, 50 ).buffer() ).toString( "latin1" ),
+                    } )?.essence || this.#file.type;
+            }
 
             this.#type = TYPES[ type ];
         }
@@ -373,7 +371,7 @@ export class LintFile {
         }
 
         // read file content
-        this.#originalData = this.#data = await this.#file.text( "utf8" );
+        this.#originalData = this.#data = await this.#file.text();
 
         // add default extension
         if ( this.#type ) {