Add missing files to .gitattributes.

Only *.sed is required, all other files are listed to be explicit.

.gitattributes

@@ -10,6 +10,14 @@ Makefile text eol=lf
 *.inc text eol=lf
 *.sha1 text eol=lf
 *.json text eol=lf
+*.sed text eol=lf
+*.cpp text eol=lf
+.gitattributes text eol=lf
+.gitignore text eol=lf
+*.hpp text eol=lf
+*.md text eol=lf
+*.ps1 text eol=crlf
+*.yml text eol=lf
 
 *.png binary
 *.bin binary