chore: add %F and mimetype to desktop file

assets/neovide.desktop

@@ -1,8 +1,9 @@
 [Desktop Entry]
 Type=Application
-Exec=neovide
+Exec=neovide %F
 Icon=neovide
 Name=Neovide (nvim)
 Keywords=Text;Editor;
 Categories=Utility;TextEditor;
 Comment=No Nonsense Neovim Client in Rust
+MimeType=text/english;text/plain;text/x-makefile;text/x-c++hdr;text/x-c++src;text/x-chdr;text/x-csrc;text/x-java;text/x-moc;text/x-pascal;text/x-tcl;text/x-tex;application/x-shellscript;text/x-c;text/x-c++;