gitignore: Set LC_COLLATE=C sort standard for file

Add a comment at the beginning of the file that shows how to sort it
this way. That heading comment line actually gets resorted elsewhere
when applying this sorting. For the rare occasions when resorting is
needed, one simply has to manually put that line back at file's top.

Signed-off-by: Marco Miller <marco.miller@ericsson.com>

.gitignore

@@ -1,15 +1,16 @@
-node_modules
-.browser_modules
-lib
+# LC_COLLATE=C sort .gitignore
+!examples/*/electron-builder.yml
+!examples/*/package.json
+!examples/*/resources/
+!examples/*/scripts
 *.log
+*.tsbuildinfo
+.browser_modules
 /packages/react-components/coverage/
 TraceCompassTutorialTraces
-trace-compass-server
-trace-compass-server.tar.gz
 TraceCompassTutorialTraces.tgz
 examples/*
-!examples/*/package.json
-!examples/*/electron-builder.yml
-!examples/*/resources/
-!examples/*/scripts
-*.tsbuildinfo
+lib
+node_modules
+trace-compass-server
+trace-compass-server.tar.gz