Change af-magic theme's branch color (#5730)

themes/af-magic.zsh-theme

@@ -27,7 +27,7 @@ else
 fi
 
 # git settings
-ZSH_THEME_GIT_PROMPT_PREFIX="$FG[075](branch:"
+ZSH_THEME_GIT_PROMPT_PREFIX="$FG[075]($FG[078]"
 ZSH_THEME_GIT_PROMPT_CLEAN=""
 ZSH_THEME_GIT_PROMPT_DIRTY="$my_orange*%{$reset_color%}"
 ZSH_THEME_GIT_PROMPT_SUFFIX="$FG[075])%{$reset_color%}"