Change REGEX_RE to allow use of / in filters

[Etiennef]

In mutation or event filtering, it is currently possible to filter using regexp, but not to use the / char in a regex.
This prevents to filter on namespaced mutation name, which is sad. My personnal example is that I wanted to filter out the mutation (core/logger/log) with the following regexp : /^((?!core\/logger\/log).)*$/ and it didn't work. Filtering with /^((?!logger).)*$/ did work as expected, but filters too much.

I checked the code in src/devtools/views/vuex/module.js an src/devtools/views/action/module.js
The regexp REGEX_RE = /^\/(.*?)\/(\w*)/ cuts the regexp at the first / encountered, making it impossible to use this char in a regexp, no matter how we try to escape it.

I see several ways to do solve it:

• I'm not sure why the .* in REGEXP_RE is not greedy. removing the ? seems to work : REGEX_RE = /^\/(.*)\/(\w*)/
• Same with the absence of $ at the end. If we assume there only is a regexp in the field (I don't know vue-devtools enough to know it it's a reasonable assumption) : REGEX_RE = /^\/(.*?)\/(\w*)$/.
• Allow escaping it with \ as we would in javascript code. I belive the right regexp for this would be REGEX_RE = /^\/((?:(?:.*?)(?:\\\/)?)*?)\/(\w*)/

I implemented the last solution, which seems cleaner because closer to the initial design that I may not fully understand, and thus less likely to have side effects. It's also closer to the javascript syntax.

I'm not 100% sure of my regexp choice, but I tested it in what seemed to be representative cases (https://gist.github.com/Etiennef/2ef33b57fc7b63e730db050f8b905ce1)