Adjust Latvian translation & add missing file entries to build.zig (#850)

Change Latvian literal translation that did not quite fit the role of
username to more appropriate.

Added missing locale files to build.zig

Reviewed-on: https://codeberg.org/fairyglade/ly/pulls/850
Reviewed-by: AnErrupTion <anerruption@disroot.org>
Co-authored-by: Galtrhan <galtrhan@gmail.com>
Co-committed-by: Galtrhan <galtrhan@gmail.com>

res/lang/lv.ini

@@ -54,7 +54,7 @@ err_xcb_conn = xcb savienojums neizdevās
 err_xsessions_dir = neizdevās atrast sesiju mapi
 err_xsessions_open = neizdevās atvērt sesiju mapi
 insert = ievietot
-login = pieteikties
+login = lietotājs
 logout = iziet
 no_x11_support = x11 atbalsts atspējots kompilācijas laikā
 normal = parastais
@@ -68,3 +68,4 @@ sleep = snauda
 wayland = wayland
 x11 = x11
 xinitrc = xinitrc
+