Add README.md

Author: axelf4

README.md

@@ -0,0 +1,13 @@
+# vim-strip-trailing-whitespace
+![](https://github.com/axelf4/vim-strip-trailing-whitespace/workflows/CI/badge.svg)
+
+Vim plugin that removes trailing whitespace
+ * **from modified lines:** Should not introduce extraneous changes into the diff, even when editing faulty files.
+ 
+   For fixing up the whole file the command `:StripTrailingWhitespace` is provided.
+ * **on save:** Lines changing under you feet breaks any flow and is a compatibility hazard.
+ 
+Achieved by maintaining a set of all edited lines with trailing whitespace,
+backed by a Splay tree where children store line number offsets.
+
+*Vim support: requires Vim 8.2+*