Update slow-compiles.md

Add missing "."

docs/slow-compiles.md

@@ -22,7 +22,7 @@ But functions and methods can also be written inline in header files. The downsi
 
 Because Catch is implemented *entirely* in headers you might think that the whole of Catch must be compiled into every translation unit that uses it! Actually it's not quite as bad as that. Catch mitigates this situation by effectively maintaining the traditional separation between the implementation code and declarations. Internally the implementation code is protected by ```#ifdef```s and is conditionally compiled into only one translation unit. This translation unit is that one that ```#define```s ```CATCH_CONFIG_MAIN``` or ```CATCH_CONFIG_RUNNER```. Let's call this the main source file.
 
-As a result the main source file *does* compile the whole of Catch every time! So it makes sense to dedicate this file to *only* ```#define```-ing the identifier and ```#include```-ing Catch (and implementing the runner code, if you're doing that). Keep all your test cases in other files. This way you won't pay the recompilation cost for the whole of Catch 
+As a result the main source file *does* compile the whole of Catch every time! So it makes sense to dedicate this file to *only* ```#define```-ing the identifier and ```#include```-ing Catch (and implementing the runner code, if you're doing that). Keep all your test cases in other files. This way you won't pay the recompilation cost for the whole of Catch.
 
 ## Practical example
 Assume you have the `Factorial` function from the [tutorial](tutorial.md#top) in `factorial.cpp` (with forward declaration in `factorial.h`) and want to test it and keep the compile times down when adding new tests. Then you should have 2 files, `tests-main.cpp` and `tests-factorial.cpp`: