Trim all trailing whitespace

The `.editorconfig` file in this repo is configured to trim all trailing
whitespace regardless of whether the line is modified.

Trims all trailing whitespace in the repository to make the codebase easier
to work with in editors that respect `.editorconfig`.

`git blame` becomes less useful on these lines but it already isn't very useful.

Commands:

```
find . -type f -name '*.h' -exec sed --in-place 's/[[:space:]]\+$//' {} \+
find . -type f -name '*.c' -exec sed --in-place 's/[[:space:]]\+$//' {} \+
```

engine/common/dedicated.c

@@ -11,7 +11,7 @@ This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU General Public License for more details.
-*/ 
+*/
 #if XASH_DEDICATED
 #include "common.h"
 #include "xash3d_mathlib.h"
@@ -205,12 +205,12 @@ void Host_InputFrame( void )
 
 void VID_InitDefaultResolution( void )
 {
-	
+
 }
 
 void Con_Init( void )
 {
-	
+
 }
 
 void R_ClearAllDecals( void )