Escalate privileges when writing to an unauthorized file also on Linux

package.json

@@ -1,6 +1,6 @@
 {
   "name": "text-buffer",
-  "version": "13.15.3",
+  "version": "13.15.4-0",
   "description": "A container for large mutable strings with annotated regions",
   "main": "./lib/text-buffer",
   "scripts": {
@@ -48,7 +48,7 @@
     "diff": "^2.2.1",
     "emissary": "^1.0.0",
     "event-kit": "^2.4.0",
-    "fs-admin": "^0.1.7",
+    "fs-admin": "^0.5.0",
     "fs-plus": "^3.0.0",
     "grim": "^2.0.2",
     "mkdirp": "^0.5.1",

spec/text-buffer-io-spec.js

@@ -448,7 +448,7 @@ describe('TextBuffer IO', () => {
     })
 
     describe('when a permission error occurs', () => {
-      if (process.platform !== 'darwin') return
+      if (process.platform === 'win32') return
 
       beforeEach(() => {
         const save = NativeTextBuffer.prototype.save

src/text-buffer.js

@@ -1921,7 +1921,8 @@ class TextBuffer {
       try {
         await this.buffer.save(destination, this.getEncoding())
       } catch (error) {
-        if (error.code === 'EACCES' && destination === filePath && process.platform === 'darwin') {
+        const canEscalate = process.platform === 'darwin' || process.platform === 'linux'
+        if (error.code === 'EACCES' && destination === filePath && canEscalate) {
           const fsAdmin = require('fs-admin')
           try {
             await this.buffer.save(fsAdmin.createWriteStream(filePath), this.getEncoding())