For user specific thing-at-point add a new property 'highlight-thing-…

[antoineB]

…rx-fn

taking a function that construct a specific regexp instead of the default.

[fgeller]

thanks @antoineB ! i guess that the ultimate form of customizing it 👍

i'll merge your work and then apply some changes - just started typing up the suggestions and realized it's quicker to just code them.

[fgeller]

@antoineB so just renamed the property to highlight-thing-regex-fn for a bit more consistency with the other names, you probably need to update your call to put the property if you change to the updated version.
I'd like to add a note to the readme for this, would you mind sharing your use case rather that me making something up?

[antoineB]

I wanted to highlight variables in a php buffer. Php variable are of the form "$[a-zA-Z_0-9]+" but the 'symbol thing-at-point does only match the "[a-zA-Z_0-9]+" part so I make a 'php-var-symbol thingy. It turns out the highlight-thing.el has a special case for 'symbol that put word boundary on the regexp it search for so I made this PR.