docs: dev-tools: gcov: Remove a stray single-quote

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Link: https://lore.kernel.org/r/20200229173515.13868-1-j.neuschaefer@gmx.netSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/dev-tools/gcov.rst

@@ -203,7 +203,7 @@ Cause
     may not correctly copy files from sysfs.
 
 Solution
-    Use ``cat``' to read ``.gcda`` files and ``cp -d`` to copy links.
+    Use ``cat`` to read ``.gcda`` files and ``cp -d`` to copy links.
     Alternatively use the mechanism shown in Appendix B.