[flang][docs][NFC] Remove stray backtick (#154974)

Remove stray backtick introduced in commit
10cd0e7.

Author: Rageking8

flang/docs/FortranLLVMTestSuite.md

@@ -72,4 +72,4 @@ The tests will be run automatically if the test suite is built following the
 instructions described [above](#running-the-llvm-test-suite-with-fortran).
 There are additional configure-time options that can be used with the gfortran 
 tests. More details about those options and their purpose can be found in 
-[`Fortran/gfortran/README.md`](https://github.com/llvm/llvm-test-suite/tree/main/Fortran/gfortran/README.md)`.
+[`Fortran/gfortran/README.md`](https://github.com/llvm/llvm-test-suite/tree/main/Fortran/gfortran/README.md).