all: fix some comments

Change-Id: Ic8faee52db43f1c669dbc8d141eeda3c7093bd29
Reviewed-on: https://go-review.googlesource.com/c/mod/+/712901
Auto-Submit: Sean Liao <sean@liao.dev>
Reviewed-by: Sean Liao <sean@liao.dev>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>

modfile/read.go

diff --git a/modfile/read.go b/modfile/read.go
index 2d74868..f58de02 100644
--- a/modfile/read.go
+++ b/modfile/read.go
@@ -94,7 +94,7 @@
 // line, the new line is added at the end of the block containing hint,
 // extracting hint into a new block if it is not yet in one.
 //
-// If the hint is non-nil buts its first token does not match,
+// If the hint is non-nil but its first token does not match,
 // the new line is added after the block containing hint
 // (or hint itself, if not in a block).
 //

module/module.go

diff --git a/module/module.go b/module/module.go
index 16e1aa7..9d3955b 100644
--- a/module/module.go
+++ b/module/module.go
@@ -261,7 +261,7 @@
 
 // importPathOK reports whether r can appear in a package import path element.
 //
-// Import paths are intermediate between module paths and file paths: we allow
+// Import paths are intermediate between module paths and file paths: we
 // disallow characters that would be confusing or ambiguous as arguments to
 // 'go get' (such as '@' and ' ' ), but allow certain characters that are
 // otherwise-unambiguous on the command line and historically used for some

semver/semver.go

diff --git a/semver/semver.go b/semver/semver.go
index 628f8fd..824b282 100644
--- a/semver/semver.go
+++ b/semver/semver.go
@@ -45,8 +45,8 @@
 
 // Canonical returns the canonical formatting of the semantic version v.
 // It fills in any missing .MINOR or .PATCH and discards build metadata.
-// Two semantic versions compare equal only if their canonical formattings
-// are identical strings.
+// Two semantic versions compare equal only if their canonical formatting
+// is an identical string.
 // The canonical invalid semantic version is the empty string.
 func Canonical(v string) string {
 	p, ok := parse(v)