Replaced my MPL snippet with License Header Manager

License Header Manager is an extension for Visual Studio.
<https://github.com/rubicon-oss/LicenseHeaderManager>

Why no one told me about this previous, I have no idea!
`¯\_(ツ)_/¯`

src/Umbraco.Community.Contentment.sln

@@ -9,6 +9,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution
 	ProjectSection(SolutionItems) = preProject
 		.editorconfig = .editorconfig
 		..\LICENSE = ..\LICENSE
+		Umbraco.Community.Contentment.sln.licenseheader = Umbraco.Community.Contentment.sln.licenseheader
 		..\VERSION = ..\VERSION
 	EndProjectSection
 EndProject
@@ -33,11 +34,6 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "GitHub", "GitHub", "{49BDDD
 		..\.github\ROADMAP.md = ..\.github\ROADMAP.md
 	EndProjectSection
 EndProject
-Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Tools", "Tools", "{56F1FA82-1108-4C75-A122-D58D759D61E2}"
-	ProjectSection(SolutionItems) = preProject
-		..\tools\insert-license-header.snippet = ..\tools\insert-license-header.snippet
-	EndProjectSection
-EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Documentation", "Documentation", "{9C956438-0434-40DD-BBA0-7F837E8FF1C8}"
 	ProjectSection(SolutionItems) = preProject
 		..\docs\README.md = ..\docs\README.md
@@ -76,7 +72,6 @@ Global
 	GlobalSection(NestedProjects) = preSolution
 		{5297EC84-5180-4489-B642-E3453B51330F} = {D4F87338-D989-4C50-BF8E-EF4AF179B459}
 		{49BDDD3C-6B40-4BE9-BD7E-10C85E55A59F} = {D4F87338-D989-4C50-BF8E-EF4AF179B459}
-		{56F1FA82-1108-4C75-A122-D58D759D61E2} = {D4F87338-D989-4C50-BF8E-EF4AF179B459}
 		{9C956438-0434-40DD-BBA0-7F837E8FF1C8} = {D4F87338-D989-4C50-BF8E-EF4AF179B459}
 		{A5294B30-2ED5-4BBA-A2DE-A07103DAE78F} = {9C956438-0434-40DD-BBA0-7F837E8FF1C8}
 		{02357F6B-DA34-47CC-BA3E-A737CEC66B0D} = {49BDDD3C-6B40-4BE9-BD7E-10C85E55A59F}

src/Umbraco.Community.Contentment.sln.licenseheader

@@ -0,0 +1,11 @@
+extensions: .cs .js .css
+/* Copyright © %CreationYear% %UserDisplayName%.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+extensions: .html
+<!-- Copyright © %CreationYear% %UserDisplayName%.
+   - This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at https://mozilla.org/MPL/2.0/. -->