BUG: Pattern "(X) " anywhere hidden with -P.

The regular expression HIDE_PRIORITY_SUBSTITUTION is not anchored, so strings that look like a priority but are not at the beginning are filtered, too.
Anchoring the regexp in the step after the highlighting has been applied is problematic due to the prepended dynamic priority highlighting string, and it also cannot be done before that because highlighting needs the information. Therefore, the filtering is moved into the AWK highlighting itself.

todo.sh

@@ -724,12 +724,14 @@ _list() {
                     print highlight("COLOR_DONE") $0 highlight("DEFAULT")
                 } else if (match($0, /^[0-9]+ \([A-Z]\)[[:space:]]/)) {
                     clr = highlight("PRI_" substr($0, RSTART + RLENGTH - 3, 1))
-                    print ( clr ? clr : highlight("PRI_X") ) $0 highlight("DEFAULT")
+                    print \
+                        (clr ? clr : highlight("PRI_X")) \
+                        (ENVIRON["HIDE_PRIORITY_SUBSTITUTION"] == "" ? $0 : substr($0, 1, RLENGTH - 4) substr($0, RSTART + RLENGTH)) \
+                        highlight("DEFAULT")
                 } else { print }
             }
           '''  \
         | sed '''
-            s/'${HIDE_PRIORITY_SUBSTITUTION:-^}'//g
             s/'${HIDE_PROJECTS_SUBSTITUTION:-^}'//g
             s/'${HIDE_CONTEXTS_SUBSTITUTION:-^}'//g
           '''                                                   \