[BUG] Cannot generate Adittional documentation

Overview of the issue

Tried to add additional documentation according to documentation, put the markdown files in a docs folder in the root, generate a summary.json inside docs and ran compodoc -p tsconfig.json --includes docs, error prompted:

[23:42:24] Error during docs\summary.json read
[23:42:24] Error during Additional documentation generation

summary.json
[
    {
        "title": "Administradores",
        "file": "administradores.md"
    }
]

Both docs and package.json inside src

Operating System, Node.js, npm, compodoc version(s)

Compodoc: 1.1.11
Npm 6.12.0

Angular CLI: 9.1.7
Node: 12.13.0
OS: win32 x64

Angular: 9.1.9
... animations, common, compiler, compiler-cli, core, forms
... language-service, platform-browser, platform-browser-dynamic
... router
Ivy Workspace: Yes

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.802.2
@angular-devkit/build-angular     0.901.7
@angular-devkit/build-optimizer   0.901.7
@angular-devkit/build-webpack     0.901.7
@angular-devkit/core              8.2.2
@angular-devkit/schematics        9.1.7
@angular/cdk                      9.2.4
@angular/cli                      9.1.7
@angular/fire                     5.4.2
@angular/flex-layout              9.0.0-beta.31
@angular/material                 9.2.4
@ngtools/webpack                  9.1.7
@schematics/angular               9.1.7
@schematics/update                0.901.7
rxjs                              6.5.5
typescript                        3.8.3
webpack                           4.42.0

Angular configuration, a package.json file in the root folder

{
  "name": "name",
  "version": "0.0.0",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e",
    "docs": "compodoc -p tsconfig.json --includes docs"
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "^9.1.9",
    "@angular/cdk": "^9.2.4",
    "@angular/common": "~9.1.9",
    "@angular/compiler": "~9.1.9",
    "@angular/core": "~9.1.9",
    "@angular/flex-layout": "^9.0.0-beta.29",
    "@angular/fire": "^5.4.2",
    "@angular/forms": "~9.1.9",
    "@angular/material": "^9.2.4",
    "@angular/platform-browser": "~9.1.9",
    "@angular/platform-browser-dynamic": "~9.1.9",
    "@angular/router": "~9.1.9",
    "@ngx-translate/core": "^12.1.2",
    "bootstrap": "^4.4.1",
    "chart.js": "2.5.0",
    "core-js": "2.4.1",
    "css-star-rating": "git+https://[e-mail]/uilibrary/css-star-rating.git",
    "echarts": "4.2.1",
    "faker": "^4.1.0",
    "firebase": ">= 5.5.7 <8",
    "flag-icon-css": "3.3.0",
    "hammerjs": "^2.0.8",
    "moment": "2.24.0",
    "ng2-charts": "2.2.2",
    "ngx-color-picker": "7.5.0",
    "ngx-custom-validators": "^9.1.0",
    "ngx-echarts": "4.1.1",
    "ngx-pagination": "3.2.1",
    "ngx-perfect-scrollbar": "^8.0.0",
    "ngx-quill": "4.8.0",
    "ngx-toastr": "^12.0.1",
    "perfect-scrollbar": "1.4.0",
    "quill": "^1.3.7",
    "rxjs": "~6.5.5",
    "tslib": "^1.10.0",
    "zone.js": "~0.10.2"
  },
  "devDependencies": {
    "@angular-devkit/build-angular": "~0.901.7",
    "@angular/cli": "~9.1.7",
    "@angular/compiler-cli": "~9.1.9",
    "@angular/language-service": "~9.1.9",
    "@types/node": "^12.11.1",
    "@types/jasmine": "~3.3.8",
    "@types/jasminewd2": "~2.0.3",
    "codelyzer": "^5.1.2",
    "jasmine-core": "~3.4.0",
    "jasmine-spec-reporter": "~4.2.1",
    "karma": "~4.1.0",
    "karma-chrome-launcher": "~2.2.0",
    "karma-coverage-istanbul-reporter": "~2.0.1",
    "karma-jasmine": "~2.0.1",
    "karma-jasmine-html-reporter": "^1.4.0",
    "protractor": "~5.4.0",
    "ts-node": "~7.0.0",
    "tslint": "~5.15.0",
    "typescript": "~3.8.3",
    "@angular-devkit/architect": "<0.900 || ^0.900.0-0 || ^9.0.0-0",
    "firebase-tools": "^7.12.0",
    "fuzzy": "^0.1.3",
    "inquirer": "^6.2.2",
    "inquirer-autocomplete-prompt": "^1.0.1"
  }
}

Compodoc installed globally or locally ?

Globally

If possible sourcecode of the file where it breaks

summary.json
[
    {
        "title": "Administradores",
        "file": "administradores.md"
    }
]

administradores.md

# Administradores

If possible your terminal logs before the error

[23:51:23] Process routes
[23:51:23]  Routes index generated
[23:51:23] Prepare pipes
[23:51:23] Prepare classes
[23:51:23] Prepare interfaces
[23:51:23] Prepare miscellaneous
[23:51:23] Process documentation coverage report
[23:51:23] Adding external markdown files
[23:51:23] Error during docs\summary.json read
[23:51:23] Error during Additional documentation generation

Motivation for or Use Case

Reproduce the error

Add docs with a md file in the root, ran compodoc -p tsconfig.json --includes docs

Related issues

Proposed incorrect package.json #4 into compodoc-demo-todomvc-angular The above link it’s a PR with the same issue but it wasn’t submitted as issue

Suggest a Fix

[alexcarrasco93]

This still doesn’t work…

[vogloblinsky]

@technsmile @alexcarrasco93 If there is a problem with UTF8 encoding support, please fill an issue for that. Thanks