Fix typos in naming section

Signed-off-by: Tim Hutt <timothy.hutt@codasip.com>

src/naming.adoc

@@ -75,7 +75,7 @@ separated from other multi-letter extensions by an underscore, e.g.,
 Standard extensions that extend the supervisor-level virtual-memory
 architecture are prefixed with the letters "Sv", followed by an alphanumeric
 name. Other standard extensions that extend the supervisor-level architecture are
-prefixed with thel letters "Ss", followed by an alphanumeric name. The name
+prefixed with the letters "Ss", followed by an alphanumeric name. The name
 must end with an alphabetical character. The second letter from the end cannot
 be numeric if the last letter is "p". These extensions are further defined in
 Volume II.
@@ -127,7 +127,7 @@ Bargle may be named "RV64IZifencei_Xargle_Xbargle".
 
 If multiple non-standard extensions are listed, they should be ordered
 alphabetically. Like other multi-letter extensions, they should be
-separated from other multi-leter extensions by an underscore.
+separated from other multi-letter extensions by an underscore.
 
 === Version Numbers