doc: avoid nonexistent PCRE2_ERROR_MEMORY error

5438fc8 (Add serialization functions and tests with updated pcre2test.
Fix PCRE2_INFO_SIZE issues., 2015-01-23) introduced the typo.

Reported-by: @sjshuck
Fixes: PCRE2Project#106

Author: carenas

doc/pcre2_serialize_decode.3

@@ -36,7 +36,7 @@ the following negative error codes:
   PCRE2_ERROR_BADDATA   \fInumber_of_codes\fP is zero or less
   PCRE2_ERROR_BADMAGIC  mismatch of id bytes in \fIbytes\fP
   PCRE2_ERROR_BADMODE   mismatch of variable unit size or PCRE version
-  PCRE2_ERROR_MEMORY    memory allocation failed
+  PCRE2_ERROR_NOMEMORY  memory allocation failed
   PCRE2_ERROR_NULL      \fIcodes\fP or \fIbytes\fP is NULL
 .sp
 PCRE2_ERROR_BADMAGIC may mean that the data is corrupt, or that it was compiled

doc/pcre2serialize.3

@@ -81,7 +81,7 @@ of serialized patterns, or one of the following negative error codes:
 .sp
   PCRE2_ERROR_BADDATA      the number of patterns is zero or less
   PCRE2_ERROR_BADMAGIC     mismatch of id bytes in one of the patterns
-  PCRE2_ERROR_MEMORY       memory allocation failed
+  PCRE2_ERROR_NOMEMORY     memory allocation failed
   PCRE2_ERROR_MIXEDTABLES  the patterns do not all use the same tables
   PCRE2_ERROR_NULL         the 1st, 3rd, or 4th argument is NULL
 .sp