fix(types): reflect chainlable NuxtLoading methods

[matjaz]

Built in NuxtLoading has chainable methods.

Types of changes

• Bug fix (a non-breaking change which fixes an issue)
• New feature (a non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Description

https://github.com/nuxt/nuxt.js/blob/17cc12f0051c9666341ad79b4391d15fbf4355d6/packages/vue-app/template/components/nuxt-loading.vue#L75-L79

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly. (PR: #)
• I have added tests to cover my changes (if not applicable, please state why)
• All new and existing tests are passing.

[codecov-io]

Codecov Report

Merging #5104 into dev will decrease coverage by 0.08%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##              dev   #5104      +/-   ##
=========================================
- Coverage   95.08%     95%   -0.09%     
=========================================
  Files          72      72              
  Lines        2421    2421              
  Branches      614     614              
=========================================
- Hits         2302    2300       -2     
- Misses         99     101       +2     
  Partials       20      20

Impacted Files	Coverage Δ
packages/vue-renderer/src/renderer.js	94.81% <0%> (-1.04%)	⬇️

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[kevinmarrec]

Nice catch @matjaz ! Changes sound logic, thanks !