Fix format of manpage

Signed-off-by: Antonio Niño Díaz <antonio_nd@outlook.com>

docs/rgbasm.5.html

@@ -65,9 +65,7 @@ Sometimes lines can be too long and it may be necessary to split them. The
 </div>
 <div class="Pp"></div>
 This works anywhere in the code except inside of strings. To split strings it is
-  needed to use
-<div>&#x00A0;</div>
-like this:
+  needed to use <b class="Sy" title="Sy">STRCAT</b> like this:
 <div class="Pp"></div>
 <div class="Bd" style="margin-left: 5.00ex;">
 <pre class="Li">

src/asm/rgbasm.5

@@ -50,7 +50,7 @@ syntax to do so is the following one:
 .Pp
 This works anywhere in the code except inside of strings. To split strings it is
 needed to use
-.It STRCAT
+.Sy STRCAT
 like this:
 .Pp
 .Bd -literal -offset indent