chore: add script to cleanup source code and documentation (#573)

Author: sindharta

Scripts/clean_up_text.sh

@@ -0,0 +1,6 @@
+# replace tabs
+git ls-files -z '*.cs' '*.md' '*.shader' '*.cginc' '*.hlsl' | xargs -0 sed -Ei 's/\t/    /g'
+
+# remove UTF-8 BOM, and trailing spaces or tabs at the end of lines
+git ls-files -z '*.cs' '*.md' '*.shader' '*.cginc' '*.hlsl' | xargs -0 sed -Ei 's/\r//g;s/\s+$//;s/\xef\xbb\xbf//g'
+