patch:
  "speller/algebra/+":
    - derive/^([zcs])h/$1/
    - derive/^([zcs])([^h])/$1h$2/
    - derive/ang$/an/
    - derive/an$/ang/
    - derive/eng$/en/
    - derive/en$/eng/
    - derive/in$/ing/
    - derive/ing$/in/
    - derive/ian$/iang/
    - derive/iang$/ian/
    - derive/uan$/uang/
    - derive/uang$/uan/
    - derive/ong$/on/
    - derive/on$/ong/