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.

1986/applin/README.md

@@ -10,7 +10,7 @@ US\
 make all
 ```
 
-## To run:
+## To use:
 
 ```sh
 ./applin

1986/bright/README.md

@@ -8,7 +8,7 @@ Walter Bright
 make all
 ```
 
-## To run:
+## To use:
 
 ```sh
 ./bright some_file

1986/hague/README.md

@@ -13,7 +13,7 @@ There is an alternate version which uses `fgets()`. See the Alternate code
 section below as well as the [bugs.md](/bugs.md) file for more details as to why
 it is worth having as an alternate version.
 
-## To run:
+## To use:
 
 ```sh
 ./hague 2>/dev/null

1986/stein/README.md

@@ -8,7 +8,7 @@ Jan Stein
 make all
 ```
 
-## To run:
+## To use:
 
 ```sh
 ./stein $(printf "\015\015"); echo