Remove unnecessary variables for autoload sources

[phongnh]

Hi @jayli,

I updated the PR a bit. Because all sources are autoloaded, variables for checks are not necessary. I removed all of them.

Thanks for great plugin. I want to disable loading some unnecessary sources, I find that it is a bit inconsistent in name, so I made a change to unify name structure.

The format will be g:easycomplete_sources_<source-file-name>, for example autoload/easycomplete/sources/ruby.vim, the variable should be g:easycomplete_sources_ruby instead of g:easycomplete_rb.

let g:easycomplete_sources_bash  = 1   "  -->  let g:easycomplete_sources_bash   = 1 
let g:easycomplete_sources_cmake = 1   "  -->  let g:easycomplete_sources_cmake  = 1 
let g:easycomplete_sources_cpp   = 1   "  -->  let g:easycomplete_sources_cpp    = 1 
let g:easycomplete_cs            = 1   "  -->  let g:easycomplete_sources_cs     = 1 
let g:easycomplete_css           = 1   "  -->  let g:easycomplete_sources_css    = 1 
let g:easycomplete_dart          = 1   "  -->  let g:easycomplete_sources_dart   = 1 
let g:easycomplete_sources_deno  = 1   "  -->  let g:easycomplete_sources_deno   = 1 
let g:easycomplete_gopls         = 1   "  -->  let g:easycomplete_sources_go     = 1 
let g:easycomplete_sources_grvy  = 1   "  -->  let g:easycomplete_sources_grvy   = 1 
let g:easycomplete_sources_html  = 1   "  -->  let g:easycomplete_sources_html   = 1 
let g:easycomplete_sources_java  = 1   "  -->  let g:easycomplete_sources_java   = 1 
let g:easycomplete_json          = 1   "  -->  let g:easycomplete_sources_json   = 1 
let g:easycomplete_kotlin        = 1   "  -->  let g:easycomplete_sources_kotlin = 1 
let g:easycomplete_sources_lua   = 1   "  -->  let g:easycomplete_sources_lua    = 1 
let g:easycomplete_nim           = 1   "  -->  let g:easycomplete_sources_nim    = 1 
let g:easycomplete_sources_php   = 1   "  -->  let g:easycomplete_sources_php    = 1 
let g:easycomplete_sources_py    = 1   "  -->  let g:easycomplete_sources_py     = 1 
let g:easycomplete_sources_r     = 1   "  -->  let g:easycomplete_sources_r      = 1 
let g:easycomplete_rb            = 1   "  -->  let g:easycomplete_sources_ruby   = 1 
let g:easycomplete_rust          = 1   "  -->  let g:easycomplete_sources_rust   = 1 
let g:easycomplete_tn            = 1   "  -->  let g:easycomplete_sources_tn     = 1 
let g:easycomplete_sources_ts    = 1   "  -->  let g:easycomplete_sources_ts     = 1 
let g:easycomplete_sources_vim   = 1   "  -->  let g:easycomplete_sources_vim    = 1 
let g:easycomplete_sources_xml   = 1   "  -->  let g:easycomplete_sources_xml    = 1 
let g:easycomplete_sources_yaml  = 1   "  -->  let g:easycomplete_sources_yaml   = 1 

Please help check this PR, and merge it if you find it makes senses, thanks.

[phongnh]

@jayli Any update on this?