README.nancy.md: Wrap a long line

Author: Alistair Turnbull

README.md

@@ -150,7 +150,8 @@ Nancy recognises these commands:
   trailing newline removed. This can be used to expand the output of a
   program run with `$run`.
 + *`$path`* Expands to the file currently being expanded, relative to the
-  input tree. This is always a template file, unless the current input path is a single file.
+  input tree. This is always a template file, unless the current input path
+  is a single file.
 + *`$realpath`* Returns the real path of the file currently being expanded.
 + *`$outputpath`* Returns the path of the output for the file currently
   being expanded.

README.nancy.md

@@ -135,7 +135,8 @@ Nancy recognises these commands:
   trailing newline removed. This can be used to expand the output of a
   program run with `\$run`.
 + *`\$path`* Expands to the file currently being expanded, relative to the
-  input tree. This is always a template file, unless the current input path is a single file.
+  input tree. This is always a template file, unless the current input path
+  is a single file.
 + *`\$realpath`* Returns the real path of the file currently being expanded.
 + *`\$outputpath`* Returns the path of the output for the file currently
   being expanded.