Change 'To run' to 'To use' in all README.md files

As in:

    sgit -e 's/# To run/# To use/g' '*README.md'

This makes consistent the message for how to use the program. 'How to
use' was chosen because one can run a program just by doing './foo' but
that doesn't imply that's how to use it but the purpose of the section
is how to use it.

1989/jar.1/README.md

@@ -18,7 +18,7 @@ make clobber all
 There is an alternate version with a slight difference that you may wish to try.
 See [Alternate code](#alternate-code) below.
 
-## To run:
+## To use:
 
 NOTE: this will run the program itself:
 
@@ -38,7 +38,7 @@ NOTE: this will run the program itself.
 make clobber alt
 ```
 
-#### To run:
+#### To use:
 
 Alternatively, you can run it directly: