Fix some typos in markdown files

ARCHITECTURE.md

@@ -325,7 +325,7 @@ get [Generator.END]() {
 
 ## Blueprints
 
-Blueprint support allows to customize the generation process.
+Blueprint support allows customizing the generation process.
 
 A Blueprint package can include any number of sub-generators, each can be a replacement blueprint, a side-by-side blueprint, or a stand alone blueprint.
 

BLUEPRINTS.md

@@ -1,6 +1,6 @@
 # JHipster Blueprints
 
-Blueprints allows to add new features or change current features.
+Blueprints allow adding new features or changing current features.
 
 ## Creating a Blueprint
 

CODE_OF_CONDUCT.md

@@ -2,7 +2,7 @@
 
 ## Our Pledge
 
-In the interest of fostering an open and welcoming environment, we as contributors and maintainers pledge to making participation in our project and our community a harassment-free experience for everyone, regardless of age, body size, disability, ethnicity, gender identity and expression, level of experience, nationality, personal appearance, race, religion, or sexual identity and orientation.
+In the interest of fostering an open and welcoming environment, we as contributors and maintainers pledge to make participation in our project and our community a harassment-free experience for everyone, regardless of age, body size, disability, ethnicity, gender identity and expression, level of experience, nationality, personal appearance, race, religion, or sexual identity and orientation.
 
 ## Our Standards