Update scripts to use `increment` (#1905)

* Replace boilerplate for increment with a call to `increment`

from new tooling. Found cases to replace using `ripgrep`[1]:
```
$ rg '\(\*\w+\)\s*\+\+' -l | grep tools | grep -v old
```

[1]: https://github.com/BurntSushi/ripgrep

* Replace boilerplate for bigger than 1 increments with the new
`increment` call

from new tooling. Found cases to replace using `ripgrep`[1]:
```
$ rg '\(\*\w+\)\s*\+=' -l | grep tools | grep -v old
```

[1]: https://github.com/BurntSushi/ripgrep

* Update examples indicating the alternative increment call for hash tables
diff --git a/examples/tracing/mallocstacks.py b/examples/tracing/mallocstacks.py
index 0def220..2f3eb25 100644
--- a/examples/tracing/mallocstacks.py
+++ b/examples/tracing/mallocstacks.py
@@ -33,6 +33,7 @@
     if (key < 0)
         return 0;
 
+    // could also use `calls.increment(key, size);`
     u64 zero = 0, *val;
     val = calls.lookup_or_init(&key, &zero);
     (*val) += size;
diff --git a/examples/tracing/strlen_count.py b/examples/tracing/strlen_count.py
index 7d2db89..49d7080 100755
--- a/examples/tracing/strlen_count.py
+++ b/examples/tracing/strlen_count.py
@@ -31,6 +31,7 @@
     u64 zero = 0, *val;
 
     bpf_probe_read(&key.c, sizeof(key.c), (void *)PT_REGS_PARM1(ctx));
+    // could also use `counts.increment(key)`
     val = counts.lookup_or_init(&key, &zero);
     (*val)++;
     return 0;
diff --git a/examples/tracing/task_switch.py b/examples/tracing/task_switch.py
index 7a73d8b..161edfb 100755
--- a/examples/tracing/task_switch.py
+++ b/examples/tracing/task_switch.py
@@ -22,6 +22,7 @@
   key.curr_pid = bpf_get_current_pid_tgid();
   key.prev_pid = prev->pid;
 
+  // could also use `stats.increment(key);`
   val = stats.lookup_or_init(&key, &zero);
   (*val)++;
   return 0;