Update README.md

README.md

@@ -9,7 +9,7 @@ Script to create a one page PDF given an EPS figure and caption file.
 ```
 
 The script `do-all` assumes that the current directory contains
-pairs of files with an `.eps`  and `.txt. extensions where the
+pairs of files with an `.eps`  and `.txt`. extensions where the
 `.txt` file is a text file with the caption of the corresponding
 `.eps` figure.