Background/float border normal float

[alexeygumirov]

Fix of the border background for compatibility with https://github.com/ray-x/lsp_signature.nvim plugin for NeoVIM.
In the LSP section for NeoVIM two highlight groups are added: FloatBorder and NormalFloat.

[NLKNguyen]

Can you put back the {{{ }}} foldings? Those help collapse code regions to make it easy to navigate, as noted at the beginning of the file. Thanks!

" Note on navigating this source code:
" - Use folding feature to collapse/uncollapse blocks of marked code
"     zM to fold all markers in this file to see the structure of the source code
"     zR to unfold all recursively
"     za to toggle a fold
"     See: http://vim.wikia.com/wiki/Folding