cue/testdata, doc, pkg: fix some it's/its typos

Closes #935
https://github.com/cuelang/cue/pull/935

GitOrigin-RevId: 859730b319dd2f68c5da07ee81c48eb46bcdd6e6
Change-Id: I47d002979b877a7794ea0f50e22292074a66c1cd
Reviewed-on: https://cue-review.googlesource.com/c/cue/+/9641
Reviewed-by: Paul Jolly <paul@myitcv.org.uk>
diff --git a/cue/testdata/cycle/compbottomnofinal.txtar b/cue/testdata/cycle/compbottomnofinal.txtar
index c19238d..57a02e8 100644
--- a/cue/testdata/cycle/compbottomnofinal.txtar
+++ b/cue/testdata/cycle/compbottomnofinal.txtar
@@ -66,7 +66,7 @@
         }
 
         #X: {
-            // Can never determine whether Y.port exists as it's resolution
+            // Can never determine whether Y.port exists as its resolution
             // depends on #Y becoming finalized, which, in turn, depends on #X
             // becoming finalized.
             if Y.port == _|_ {
@@ -82,7 +82,7 @@
         #Y: regexp.FindNamedSubmatch(#userHostPort, #X.port)
 
         #X: {
-            // Can never determine whether Y.port exists as it's resolution
+            // Can never determine whether Y.port exists as its resolution
             // depends on #Y becoming finalized, which, in turn, depends on #X
             // becoming finalized.
             if Y.port == _|_ {
@@ -110,7 +110,7 @@
         #Y: regexp.FindNamedSubmatch(#userHostPort, #X.port)
 
         #X: {
-            // Can never determine whether Y.port exists as it's resolution
+            // Can never determine whether Y.port exists as its resolution
             // depends on #Y becoming finalized, which, in turn, depends on #X
             // becoming finalized.
             if Y.port == _|_ {
@@ -130,7 +130,7 @@
         }
 
         #X: {
-            // Can never determine whether Y.port exists as it's resolution
+            // Can never determine whether Y.port exists as its resolution
             // depends on #Y becoming finalized, which, in turn, depends on #X
             // becoming finalized.
             if Y.port == _|_ {
@@ -146,7 +146,7 @@
 
     p5: {
         #X: {
-            // Can never determine whether Y.port exists as it's resolution
+            // Can never determine whether Y.port exists as its resolution
             // depends on #Y becoming finalized, which, in turn, depends on #X
             // becoming finalized.
             if Y.port == _|_ {
@@ -168,7 +168,7 @@
 
     p6: {
         #X: {
-            // Can never determine whether Y.port exists as it's resolution
+            // Can never determine whether Y.port exists as its resolution
             // depends on #Y becoming finalized, which, in turn, depends on #X
             // becoming finalized.
             if Y.port == _|_ {
diff --git a/doc/tutorial/basics/2_types/56_optional.txt b/doc/tutorial/basics/2_types/56_optional.txt
index 78c4448..3c5e11e 100644
--- a/doc/tutorial/basics/2_types/56_optional.txt
+++ b/doc/tutorial/basics/2_types/56_optional.txt
@@ -7,7 +7,7 @@
 
 -- text.md --
 Struct is the most important composite type in CUE.
-It's members are called fields.
+Its members are called fields.
 
 A struct field may be optional.
 One can use an optional field to indicate what the type should be if it were
diff --git a/pkg/internal/context.go b/pkg/internal/context.go
index a8ff4fd..8b677e7 100644
--- a/pkg/internal/context.go
+++ b/pkg/internal/context.go
@@ -25,7 +25,7 @@
 	"github.com/cockroachdb/apd/v2"
 )
 
-// CallCtxt is passed to builtin implementations that need to use a cue.Value. This is an internal type. It's interface may change.
+// CallCtxt is passed to builtin implementations that need to use a cue.Value. This is an internal type. Its interface may change.
 type CallCtxt struct {
 	ctx     *adt.OpContext
 	builtin *Builtin