Misc: bash, rust, helix

- Fix: `.bashrc` not loaded when `.bash_login` doesn't exist
- Fix: Rust install script error when `cc` doesn't exist
- Style: use tabs
- Helix: use tabs for bash, toml, & markdown
- Helix: highlight rust scripts

auto/bash/bash

@@ -39,10 +39,24 @@ EOF
 if [ -f ~/.bash_profile ]; then
 	mv ~/.bash_profile ~/.bash_login
 fi
-cat >> ~/.bash_login << 'EOF'
+if [ -f ~/.bash_login ]; then
+	cat >> ~/.bash_login << 'EOF'
 
 # custom
 
+EOF
+else
+	cat >> ~/.bash_login << 'EOF'
+
+# custom
+
+if [ -f ~/.bashrc ]; then
+	. ~/.bashrc
+fi
+
+EOF
+fi
+cat >> ~/.bash_login << 'EOF'
 if [ -z "$TMUX" ] && [ -n "$SSH_TTY" ]; then
 	tput sc
 	tput smso