Simple maintenance improvements (#1918)

* Use license file from gnu.org

Downloaded from:
https://www.gnu.org/licenses/gpl-3.0.txt

* Add missing final newline

* Fix link

* Fix shellcheck warnings

* Move donation header one level up

* Fix typos

* Stop mixing tabs and spaces

* Trim trailing whitespace

cmake/Cache.cmake

@@ -27,4 +27,3 @@ if(CACHE_BINARY)
 else()
   message(WARNING "${CACHE_OPTION} is enabled but was not found. Not using it")
 endif()
-

cmake/CompilerWarnings.cmake

@@ -1,6 +1,6 @@
 # from here:
 #
-# https://github.com/lefticus/cppbestpractices/blob/master/02-Use_the_Tools_Avai lable.md
+# https://github.com/lefticus/cppbestpractices/blob/master/02-Use_the_Tools_Available.md
 
 function(set_project_warnings project_name)
   option(WARNINGS_AS_ERRORS "Treat compiler warnings as errors" TRUE)

cmake/Sanitizers.cmake

@@ -63,4 +63,4 @@ function(enable_sanitizers project_name)
     endif()
   endif()
 
-endfunction()
+endfunction()

cmake/StandardProjectSettings.cmake

@@ -31,4 +31,4 @@ if(ENABLE_IPO)
   else()
     message(SEND_ERROR "IPO is not supported: ${output}")
   endif()
-endif()
+endif()

cmake/modules/MacOSXBundleInfo.plist.in

@@ -3,7 +3,7 @@
 <plist version="1.0">
 <dict>
 	<key>CFBundleDevelopmentRegion</key>
- 	<string>English</string>
+	<string>English</string>
 	<key>CFBundleExecutable</key>
 	<string>flameshot</string>
 	<key>CFBundleGetInfoString</key>
@@ -37,10 +37,10 @@
 	<key>NSHighResolutionCapable</key>
 	<string>True</string>
 	<key>LSUIElement</key>
-    <string>1</string>
-    <key>NSPhotoLibraryAddUsageDescription</key>
-    <string>Application requires access to save screenshots to your gallery</string>
-    <key>NSSupportsAutomaticGraphicsSwitching</key>
-    <true/>
+	<string>1</string>
+	<key>NSPhotoLibraryAddUsageDescription</key>
+	<string>Application requires access to save screenshots to your gallery</string>
+	<key>NSSupportsAutomaticGraphicsSwitching</key>
+	<true/>
 </dict>
 </plist>