perf: don't emit event lnlayhint when content is none

[Gehbt]

before:

after:

[pkg-pr-new]

Open in Stackblitz

vue-component-meta

pnpm add https://pkg.pr.new/vuejs/language-tools/vue-component-meta@4776

vue-component-type-helpers

pnpm add https://pkg.pr.new/vuejs/language-tools/vue-component-type-helpers@4776

@vue/language-core

pnpm add https://pkg.pr.new/vuejs/language-tools/@vue/language-core@4776

@vue/language-plugin-pug

pnpm add https://pkg.pr.new/vuejs/language-tools/@vue/language-plugin-pug@4776

@vue/language-server

pnpm add https://pkg.pr.new/vuejs/language-tools/@vue/language-server@4776

@vue/language-service

pnpm add https://pkg.pr.new/vuejs/language-tools/@vue/language-service@4776

vue-tsc

pnpm add https://pkg.pr.new/vuejs/language-tools/vue-tsc@4776

@vue/typescript-plugin

pnpm add https://pkg.pr.new/vuejs/language-tools/@vue/typescript-plugin@4776

commit: b19cd2c

[johnsoncodehk]

LGTM, thanks!