docs: fix typo in example usage "occured" -> "occurred"

Also change it in some test descriptions where it matters even less.

docs/index.md

@@ -161,7 +161,7 @@ Alternatively, such error assertions on multi return value functions can be simp
 Similar, asserting that no error occurred is supported, too (where the other return values are allowed to take on any value):
 
 ```go
-Ω(MultipleReturnValuesFunc()).Error().ShouldNot(HaveOccured())
+Ω(MultipleReturnValuesFunc()).Error().ShouldNot(HaveOccurred())
 ```
 
 ### Annotating Assertions

internal/async_assertion_test.go

@@ -180,7 +180,7 @@ var _ = Describe("Asynchronous Assertions", func() {
 				Ω(ig.RegisteredHelpers).Should(ContainElement("(*AsyncAssertion).match"))
 			})
 
-			It("renders the matcher's error if an error occured", func() {
+			It("renders the matcher's error if an error occurred", func() {
 				ig.G.Eventually(ERR_MATCH).WithTimeout(50 * time.Millisecond).WithPolling(10 * time.Millisecond).Should(SpecMatch())
 				Ω(ig.FailureMessage).Should(ContainSubstring("Timed out after"))
 				Ω(ig.FailureMessage).Should(ContainSubstring("The matcher passed to Eventually returned the following error:"))
@@ -443,7 +443,7 @@ var _ = Describe("Asynchronous Assertions", func() {
 				Ω(ig.RegisteredHelpers).Should(ContainElement("(*AsyncAssertion).match"))
 			})
 
-			It("renders the matcher's error if an error occured", func() {
+			It("renders the matcher's error if an error occurred", func() {
 				ig.G.Consistently(ERR_MATCH).Should(SpecMatch())
 				Ω(ig.FailureMessage).Should(ContainSubstring("Failed after"))
 				Ω(ig.FailureMessage).Should(ContainSubstring("The matcher passed to Consistently returned the following error:"))
@@ -1575,7 +1575,7 @@ sprocket:
 			})
 
 			When("the actual error is because there was an assertion failure in the function, and there are return values", func() {
-				It("emits a clear message about the error having occured", func() {
+				It("emits a clear message about the error having occurred", func() {
 					_, file, line, _ := runtime.Caller(0)
 					ig.G.Eventually(func(g Gomega) int {
 						g.Expect(true).To(BeFalse())