How to do autocorrect?

Question

Regular Expressions

Hello, please help me to complete the task.
There are 1k+ pages in which all links to pages are registered with .html, you need to change html to htm through autocorrect,
for this you need a regular expression something like href="(any characters).html" to href= "(any characters).htm"
changing from pure .html to .htm is not an option

Answer 1

(href="[^"]+\.)html"
replace with
\1htm