Fine-tune dirhistory plugin mappings for Mac (#6580)

See https://github.com/robbyrussell/oh-my-zsh/pull/6533#issuecomment-360878060

plugins/dirhistory/dirhistory.plugin.zsh

@@ -120,7 +120,9 @@ zle -N dirhistory_zle_dirhistory_back
 bindkey "\e[3D" dirhistory_zle_dirhistory_back
 bindkey "\e[1;3D" dirhistory_zle_dirhistory_back
 # Mac teminal (alt+left/right)
-bindkey "^[b" dirhistory_zle_dirhistory_back
+if [[ "$TERM_PROGRAM" == "Apple_Terminal" ]]; then
+  bindkey "^[b" dirhistory_zle_dirhistory_back
+fi
 # Putty:
 bindkey "\e\e[D" dirhistory_zle_dirhistory_back
 # GNU screen:
@@ -129,7 +131,9 @@ bindkey "\eO3D" dirhistory_zle_dirhistory_back
 zle -N dirhistory_zle_dirhistory_future
 bindkey "\e[3C" dirhistory_zle_dirhistory_future
 bindkey "\e[1;3C" dirhistory_zle_dirhistory_future
-bindkey "^[f" dirhistory_zle_dirhistory_future
+if [[ "$TERM_PROGRAM" == "Apple_Terminal" ]]; then
+  bindkey "^[f" dirhistory_zle_dirhistory_future
+fi
 bindkey "\e\e[C" dirhistory_zle_dirhistory_future
 bindkey "\eO3C" dirhistory_zle_dirhistory_future