chore: fix tsconfig usage problem, add comments

Author: JounQin

packages/eslint-mdx/tsconfig.json

@@ -1,5 +1,5 @@
 {
-  "extends": "../../tsconfig.base",
+  "extends": "../../tsconfig.lib",
   "compilerOptions": {
     "composite": true,
     "rootDir": "src",

packages/eslint-plugin-mdx/tsconfig.json

@@ -1,5 +1,5 @@
 {
-  "extends": "../../tsconfig.base",
+  "extends": "../../tsconfig.lib",
   "compilerOptions": {
     "composite": true,
     "rootDir": "src",

tsconfig.base.json

@@ -1,7 +1,11 @@
 {
-  "extends": "./node_modules/@1stg/tsconfig/node",
+  // used by @pkgr/rollup and ESLint
+  "extends": "./tsconfig.lib",
   "compilerOptions": {
-    "strictFunctionTypes": false,
-    "strictNullChecks": false
+    "baseUrl": ".",
+    "paths": {
+      "eslint-mdx": ["packages/eslint-mdx/src"],
+      "eslint-plugin-mdx": ["packages/eslint-plugin-mdx/src"]
+    }
   }
 }

tsconfig.eslint.json

@@ -1,4 +1,5 @@
 {
+  // used by tsconfig-paths/register from synckit
   "extends": "./tsconfig.base",
   "compilerOptions": {
     "noEmit": true

tsconfig.json

@@ -0,0 +1,8 @@
+{
+  // used by all files but do not includes paths
+  "extends": "./node_modules/@1stg/tsconfig/node",
+  "compilerOptions": {
+    "strictFunctionTypes": false,
+    "strictNullChecks": false
+  }
+}