Fixed a small spelling mistake

Merges https://github.com/espressif/esp-idf/pull/3089

docs/en/api-reference/system/intr_alloc.rst

@@ -93,10 +93,9 @@ A handler will never be called when disabled, while **its source may still be tr
 
 Sources attached to non-shared interrupt do not support this feature.
 
-Though the framework support this feature, you have to use it *very carefully*. There usually exist 2 ways to stop a interrupt from being triggered: *disable the sourse* or *mask peripheral interrupt status*.
+Though the framework support this feature, you have to use it *very carefully*. There usually exist 2 ways to stop a interrupt from being triggered: *disable the source* or *mask peripheral interrupt status*.
 IDF only handles the enabling and disabling of the source itself, leaving status and mask bits to be handled by users. **Status bits should always be masked before the handler responsible for it is disabled,
-or the status should be handled in other enabled interrupt properly**. You may leave some status bits unhandled if you just disable one of all the handlers without mask the status bits, which causes the interrupt being triggered infinitely,
-and finally a system crash.
+or the status should be handled in other enabled interrupt properly**. You may leave some status bits unhandled if you just disable one of all the handlers without masking the status bits, which causes the interrupt to trigger infinitely resulting in a system crash.
 
 API Reference
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