Improve greph

Using grep directly could result in "binary file matches" without any
useful info.

This would happen e.g. after renaming some files with badly-encoded
filenames.  Bash history builtin seems to address such cases better.

dotfiles/bash/main.bashrc

 }
 
 greph() {
-    <"$HOME/.bash_history" grep "$@"
+    history | sed 's/^  *//; s/  / /' | cut -d' ' -f2- | grep "$@"
 }
 
 gitcd() {