LibPDF: Move Type1FontProgram to use AK::Error instead of PDF::Error

Makes some of the errors a bit less descriptive. But this is pretty
stable by now and the errors fire basically never, so that seems ok.

Needing the explicit `AK::` prefix is a bit awkward, but that'll go
away once this class moves out of LibPDF.

Move error() into the two subclasses. I'll remove it from CFF in
a follow-up.

No real behavior change.

Userland/Libraries/LibPDF/Fonts/PS1FontProgram.cpp

@@ -237,4 +237,19 @@ bool PS1FontProgram::seek_name(Reader& reader, ByteString const& name)
     return false;
 }
 
+Error PS1FontProgram::error(
+    ByteString const& message
+#ifdef PDF_DEBUG
+    ,
+    SourceLocation loc
+#endif
+)
+{
+#ifdef PDF_DEBUG
+    dbgln("\033[31m{} Type 1 font error: {}\033[0m", loc, message);
+#endif
+
+    return Error { Error::Type::MalformedPDF, message };
+}
+
 }