doc: remove mention of glibc 2.10+

We already require glibc 2.27+, so mentioning a much older version here
is redundant.

Author: fanquake

doc/reduce-memory.md

@@ -43,7 +43,7 @@ threads take up 8MiB for the thread stack on a 64-bit system, and 4MiB in a
 
 ## Linux specific
 
-By default, since glibc `2.10`, the C library will create up to two heap arenas per core. This is known to cause excessive memory usage in some scenarios. To avoid this make a script that sets `MALLOC_ARENA_MAX` before starting bitcoind:
+By default, glibc will create up to two heap arenas per core. This is known to cause excessive memory usage in some scenarios. To avoid this make a script that sets `MALLOC_ARENA_MAX` before starting bitcoind:
 
 ```bash
 #!/usr/bin/env bash

src/rpc/node.cpp

@@ -163,7 +163,7 @@ static RPCHelpMan getmemoryinfo()
                 {
                     {"mode", RPCArg::Type::STR, RPCArg::Default{"stats"}, "determines what kind of information is returned.\n"
             "  - \"stats\" returns general statistics about memory usage in the daemon.\n"
-            "  - \"mallocinfo\" returns an XML string describing low-level heap state (only available if compiled with glibc 2.10+)."},
+            "  - \"mallocinfo\" returns an XML string describing low-level heap state (only available if compiled with glibc)."},
                 },
                 {
                     RPCResult{"mode \"stats\"",