Add simplified Github Issue/PR URL recognition

Now that we can click on URLs and files we could improve a bit on this and add recognition for a simplified version of github issues and pull requests.

I often use Spyder to develop spyder so this would be really handy, as I often see myself opening a browser tab and opening the referenced issue on sections of code.

Option 1

Simply include full urls to issues on our code base so we can click on them on the spot

Pros: No need to change code, just update the references Cons: Long urls might crop up in the docstrings and comments

# See: https://github.com/spyder-ide/spyder/issues/NNNN
'''See: https://github.com/spyder-ide/spyder/issues/NNNN'''

Option 2

Add a shorthand syntax for github issues and PRs that makes life easy for us.

Pros: Shorter “links” Cons: we need to update the code a bit + update the references

# See issue spyder-ide/spyder#NNNN
# See PR spyder-ide/spyder#NNNN
'''See PR spyder-ide/spyder#NNNN'''

This syntax would apply to both issues and PRs, since they are the “same” on github

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What do you think @spyder-ide/core-developers ?

[goanpeca]

I also prefer option 2, but it is not me who is going to implement it 😄

@jitseniesen The basic machinery is already implemented so, it is just a matter of deciding a format regex and adding a couple of lines of code.

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@bcolsen interesting!

Option 3++

# See issue gh:spyder-ide/spyder#NNNN`
# See PR gh:spyder-ide/spyder#NNNN
'''See PR gh:spyder-ide/spyder#NNNN'''

And optional, so we give priority to github if not found

Something like (needs further thinking!)

r'((?:\w\w:)?[\w\-_]*/[\w\-_]*#[\d]*)'

Would match either of these

hello gh:spyder-ide/spyder#1245 hello
hello gl:spyder-ide/spyder#567 hello 
hello bb:spyder-ide/spyder#8995 hello 
hello spyder-ide/spyder#8995 hello   # Default to github

gh -> github gl: gitlab bb: bitbucket

[ccordoba12]

Eventually, we can perhaps add a project option so that we can leave out the spyder-ide/spyder and just write issue #9463 in the code

I agree with this, it’d be really nice!