goimports: add page (#3308)

pages/common/goimports.md

@@ -0,0 +1,20 @@
+# goimports
+
+> Updates Go import lines, adding missing ones and removing unreferenced ones.
+> More information: <https://godoc.org/golang.org/x/tools/cmd/goimports>.
+
+- Display the completed import source file:
+
+`goimports {{file}}.go`
+
+- Write the result back to the source file instead of the standard output:
+
+`goimports -w {{file}}.go`
+
+- Display diffs and write the result back to the source file:
+
+`goimports -w -d {{file}}.go`
+
+- Set the import prefix string after 3rd-party packages (comma-separated list):
+
+`goimports -local {{/path/to/package}} {{file}}.go`