disable or substitute "compatible" icons that cannot be displayed by the stock Menlo on macOS

internal/icons.zsh

@@ -432,7 +432,7 @@ function _p9k_init_icons() {
         RIGHT_SUBSEGMENT_SEPARATOR     '\uE0B3'               # 
         CARRIAGE_RETURN_ICON           '\u21B5'               # ↵
         ROOT_ICON                      '\u26A1'               # ⚡
-        SUDO_ICON                      '\uE0A2'               # 
+        SUDO_ICON                      ''
         RUBY_ICON                      'Ruby'
         AWS_ICON                       'AWS'
         AWS_EB_ICON                    '\U1F331'              # 🌱

internal/wizard.zsh

@@ -1217,8 +1217,10 @@ function generate_config() {
   fi
 
   if [[ $POWERLEVEL9K_MODE == compatible ]]; then
-    # Many fonts don't have the gear icon.
+    # Many fonts don't have the gear or the lock icon.
     sub BACKGROUND_JOBS_VISUAL_IDENTIFIER_EXPANSION "'⇶'"
+    uncomment 'typeset -g POWERLEVEL9K_DIR_NOT_WRITABLE_VISUAL_IDENTIFIER_EXPANSION'
+    sub DIR_NOT_WRITABLE_VISUAL_IDENTIFIER_EXPANSION "'∅'"
   fi
 
   if [[ $POWERLEVEL9K_MODE == (awesome-patched|awesome-fontconfig) && $cap_python == 0 ]]; then