internal/gapicgen: add dir context to docs

Change-Id: If5af3446ac4926364b1772c062a2f165f2b1da42
Reviewed-on: https://code-review.googlesource.com/c/gocloud/+/49271
Reviewed-by: Noah Dietz <ndietz@google.com>
diff --git a/internal/gapicgen/cmd/genbot/README.md b/internal/gapicgen/cmd/genbot/README.md
index 93f8c5e..355575e 100644
--- a/internal/gapicgen/cmd/genbot/README.md
+++ b/internal/gapicgen/cmd/genbot/README.md
@@ -19,6 +19,7 @@
 1. Run:
 
 ```
+cd /path/to/internal/gapicgen
 go run cloud.google.com/go/internal/gapicgen/genbot \
     --accessToken=11223344556677889900aabbccddeeff11223344 \
     --githubUsername=jadekler \
diff --git a/internal/gapicgen/cmd/genlocal/README.md b/internal/gapicgen/cmd/genlocal/README.md
index 4890847..ed05721 100644
--- a/internal/gapicgen/cmd/genlocal/README.md
+++ b/internal/gapicgen/cmd/genlocal/README.md
@@ -26,5 +26,6 @@
 ## Running
 
 ```
+cd /path/to/internal/gapicgen
 go run cloud.google.com/go/internal/gapicgen/genlocal
 ```
\ No newline at end of file
diff --git a/internal/gapicgen/cmd/genmgr/README.md b/internal/gapicgen/cmd/genmgr/README.md
index d57cb2e..8da9857 100644
--- a/internal/gapicgen/cmd/genmgr/README.md
+++ b/internal/gapicgen/cmd/genmgr/README.md
@@ -26,6 +26,7 @@
 Note: this may change your ~/.gitconfig and ~/.gitcookies.
 
 ```
+cd /path/to/internal/gapicgen
 go run cloud.google.com/go/internal/gapicgen/genmgr \
     --accessToken=11223344556677889900aabbccddeeff11223344 \
     --githubName="Jean de Klerk" \