How to add words to omni completion dictionary?

For example, if I'm in an html file and it type < then tab, I'll get a list of !doctypes that I can use. However "<!DOCTYPE html>" is not included, and I would like to add it. How do I go about doing this?

Solution

Take a look at this repo for html5 omnicompletion.

Alternatively, you can copy $VIMRUNTIME/autoload/htmlcomplete.vim to your ~/.vim/autoload folder and edit it there. This will override it with your custom file.

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>               \ '!DOCTYPE html>',
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<           if &filetype == 'html' && exists("uppercase_tag") && uppercase_tag == 1 && item !~ 'DOCTYPE'
<               let item = toupper(item)
<           endif
<           if item =~ 'DOCTYPE'
<               let abbr = 'DOCTYPE '.matchstr(item, 'DTD \zsX\?HTML .\{-}\ze\/\/')
---
>           if item == '!DOCTYPE html>'
>               let abbr = "DOCTYPE HTML 5"
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<               let abbr = item
---
>               if &filetype == 'html' && exists("uppercase_tag") && uppercase_tag == 1 && item !~ 'DOCTYPE'
>                   let item = toupper(item)
>               endif
>               if item =~ 'DOCTYPE'
>                   let abbr = 'DOCTYPE '.matchstr(item, 'DTD \zsX\?HTML .\{-}\ze\/\/')
>               else
>                   let abbr = item
>               endif
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>       elseif line=~ '<!DOCTYPE html>'
>           let b:html_omni_flavor = 'html5'
>           let b:html_doctype = 1
>           break