Meson support

[mid-kid]

Meson files are called meson.build, and the syntax contains two pairs of start/end markers:

• if / endif
• foreach / endforeach

I'm thankfully not aware of any other support from this plugin that this language would require :)

[shyun3]

Not sure the author is adding support for more languages, but I added this to my own fork here: https://github.com/shyun3/vim-endwise/commit/e3785c4e09fe8df729d8d00ea7f6faf08285260a