Feature: Add Support for PHP HEREDOC Strings

[phatsk]

PHP has support for HEREDOC strings. This allows large string blocks to be set between delimiters and vim supports syntax highlighting within these blocks.

In PHP in vim, using a HEREDO specifier such as SQL will cause vim to highlight the given block:

<?php
$my_query = <<<SQL
SELECT * FROM my_tables WHERE foo='bar';
SQL;

This proposal is to have the same kind of support for GraphQL queries:

<?php
$my_query = <<<GQL
{
    posts {
        id
        title
        author
    }
    category
}
GQL;

Screenshot

Vim Version

NVIM v0.5.0-nightly
Build type: Release
LuaJIT 2.0.5
Compilation: /usr/local/Homebrew/Library/Homebrew/shims/mac/super/clang -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=1 -DNDEBUG -Wall -Wextra -pedantic -Wno-unused-parameter -Wstrict-prototypes -std=gnu99 -Wshadow -Wconversion -Wmissing-prototypes -Wimplicit-fallthrough -Wvla -fstack-protector-strong -fno-common -fdiagnostics-color=auto -DINCLUDE_GENERATED_DECLARATIONS -D_GNU_SOURCE -DNVIM_MSGPACK_HAS_FLOAT32 -DNVIM_UNIBI_HAS_VAR_FROM -DMIN_LOG_LEVEL=3 -I/tmp/neovim-20200316-52073-155cxzr/build/config -I/tmp/neovim-20200316-52073-155cxzr/src -I/usr/local/include -I/tmp/neovim-20200316-52073-155cxzr/deps-build/include -I/Library/Developer/CommandLineTools/SDKs/MacOSX10.15.sdk/usr/include -I/usr/local/opt/gettext/include -I/tmp/neovim-20200316-52073-155cxzr/build/src/nvim/auto -I/tmp/neovim-20200316-52073-155cxzr/build/include
Compiled by zachowen@MacBook-Pro

Features: +acl +iconv +tui
See ":help feature-compile"

   system vimrc file: "$VIM/sysinit.vim"
  fall-back for $VIM: "/usr/local/Cellar/neovim/HEAD-2b00d1d/share/nvim"

Run :checkhealth for more info

[jparise]

@phatsk I just added PHP support. Let me know how it works or if you run into any issues with it.

Thanks for the suggestion!