[docs] Fix code blocks overflowing page width (#23829)

Fix code blocks overflowing page width

docs/feature_macros.md

@@ -252,11 +252,15 @@ You can send arbitrary keycodes by wrapping them in:
 
 For example:
 
-    SEND_STRING(SS_TAP(X_HOME));
+```c
+SEND_STRING(SS_TAP(X_HOME));
+```
 
 Would tap `KC_HOME` - note how the prefix is now `X_`, and not `KC_`. You can also combine this with other strings, like this:
 
-    SEND_STRING("VE"SS_TAP(X_HOME)"LO");
+```c
+SEND_STRING("VE"SS_TAP(X_HOME)"LO");
+```
 
 Which would send "VE" followed by a `KC_HOME` tap, and "LO" (spelling "LOVE" if on a newline).
 
@@ -266,7 +270,9 @@ Delays can be also added to the string:
 
 For example:
 
-    SEND_STRING("VE" SS_DELAY(1000) SS_TAP(X_HOME) "LO");
+```c
+SEND_STRING("VE" SS_DELAY(1000) SS_TAP(X_HOME) "LO");
+```
 
 Which would send "VE" followed by a 1-second delay, then a `KC_HOME` tap, and "LO" (spelling "LOVE" if on a newline, but delayed in the middle).
 
@@ -284,7 +290,9 @@ There's also a couple of mod shortcuts you can use:
 These press the respective modifier, send the supplied string and then release the modifier.
 They can be used like this:
 
-    SEND_STRING(SS_LCTL("a"));
+```c
+SEND_STRING(SS_LCTL("a"));
+```
 
 Which would send Left Control+`a` (Left Control down, `a`, Left Control up) - notice that they take strings (eg `"k"`), and not the `X_K` keycodes.