new_tex_uwletter: remove itself from generated directories

The install script was being copied into every new letter directory
it created. Delete it after unpacking so new letter directories only
contain the template itself.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

new_tex_uwletter

@@ -23,6 +23,7 @@ then
     mv "$WORK_DIR" "$1"
     cd "$1"
     mv "washington_letterhead_letter-matrix-deptartment.tex" "$(basename "$1").tex"
+    rm -f "new_tex_uwletter"
 
     # create a symlink farm for the fonts
     rm -rf ./fonts/*