Fix more typos in src files

src/thermo.cpp

@@ -1054,7 +1054,7 @@ int Thermo::add_variable(const char *id)
    compute a single thermodynamic value, word is any keyword in custom list
    called when a variable is evaluated by Variable class
    return value as double in answer
-   return 0 if str is recoginzed keyword, 1 if unrecognized
+   return 0 if str is recognized keyword, 1 if unrecognized
    customize a new keyword by adding to if statement
 ------------------------------------------------------------------------- */